I have a client who wants to host a single, branded community with three sub-communities.
Has anyone done this successfully? Would Groups or Categories work best?
The sub-communities will need to be uniquely branded, with different member experiences and utilize different features and functionality.
All three communities will be managed by the same Community Manager or team.
I would love to hear about how you did this and see any examples that you’re willing to share.
You would need to create 3 groups for permissions purposes. Then you would need to create 3 categories for the 3 ‘sub communities’
eg.
Create:
Group 1
Group 2
Group 3
Then create:
Category 1 (for Group 1) - Category security permissions are: ‘Group 1 create/reply/see’
Category 2 (for Group 2) - Category security permissions are: ‘Group 2 create/reply/see’
Category 3 (for Group 3) - Category security permissions are: ‘Group 3 create/reply/see’
This going to need separate forums, though.
To add to @ondrej you would need 2 groups per community. The members group with authorized managers as owners of the member’s group. Then you need your community manager group that would also be category mods.
If Self hosted Category Restricter plugin can be used to extend category mods and full site mods abilities. It adds the ability to silence users from posting in a category..
So you would need a main site team for assistance in full suspensions and full silences.
What kind of interactions do you expect across these sub-communities?
I’m thinking of questions like:
Do you want members in one to be able to freely participate in the others?
Should it feel like one larger community to them? Or should it feel like they are moving between completely different communities when they participate in one vs. the other?
Do you want conversations in one to be able to cross over into the others?
For example, do you expect or want to encourage a lot of cross-linking of discussions, or quoting pieces of one conversation in the other, etc? Or do you think that kind of behavior is unlikely, not worth encouraging, or even worth discouraging?
Can you share any examples of the different features and functionality you expect each to use?
I can imagine a few different things you may have in mind here, but any examples you can share to help illustrate further what you’re thinking would be helpful.
Great questions 
Do you want members in one to be able to freely participate in the others?
No, it would be so unlikely that a member from one would ever want to join or engage in one of the other communities.
Do you want conversations in one to be able to cross over into the others?
No, there will be no crossover. They are completely separate subject matters with different target members.
Can you share any examples of the different features and functionality you expect each to use?
Interesting stuff.
Some of this makes me wonder whether it may be better off keeping these as three separate sites. Has that been ruled out? If so, why?
Here’s my thinking – so far, it seems like the motivation for putting these all under one site is for the convenience of the team managing them. But maybe there are other ways to approach that. Applying configuration changes to multiple communities feels like a technical problem that could be solved in other ways, and keeping them separate allows for greater freedom to do things differently in each, if it’s determined that each community as different needs (which could further diverge as the communities evolve).
On the other hand, I see a hint of a few exceptions to how I’ve characterized things:
A single branded landing/home page with three links to the unique communities
Why is this important?
If people in these communities are completely separate from each other, who is it that benefits from seeing these all in one place?
Perhaps the answer here leads to some key insight I’m missing so far.
Again, I feel like this could be addressed in another way. If it’s just a home page with three links, maybe with some content pulled in dynamically, that could be implemented outside of the site.
Now all that said, if revisiting the above doesn’t feel helpful and the decision has been made that all of these should live under one site, we can bring the conversation back to your original questions about how to do that, just keeping what you’ve shared so far in mind as context.
This is really helpful Dave, I appreciate the feedback and suggestions!
At this point, we’re really at the discovery stage - trying to figure out exactly how we want these communities to work (from a member perspective, from a Community Manager perspective and from an organisational perspective). Nothing has been ruled out at this stage.
You have brought up a lot of interesting points and I have some questions for my stakeholders.
I’m going to present what I’ve learnt here plus get answers to those clarifying questions. I’ll come back to this thread once I have that clarity. I’m excited to figure out the best approach 
Can you share a little more about this? After the helpful advice and questions on this thread, I decided to present two options for my client.
Single site with multiple communities
Multiple sites
The main reason for exploring a single site set-up is for one Community Manager to be able to manage all three. It’s not cost-motivated.
I would suggest a lean approach here for starters.
What I mean by that is that it may help to design specific solutions for particular use cases first, put them into practice, and iterate. Perhaps it evolves into a full-fledged cross-community dashboard for the community team, or maybe what’s “good enough” is much smaller than that.
For example, the CM could first use Discourse Hub to be able to see a feed from all three communities and see when each has outstanding flags that need attention.
A step further could be to use chat channel(s) in one of them as “home base” and configure a feed of notifications from the review queue across all communities first, to aid in moderation across all of them.
For metrics and reporting, starting with a set of bookmarks to the admin UI areas or data explorer reports in each community could be a simple starting point.
A step further could be to set up an AI generated report with Discourse Automation that pushes a report to a PM in each, aggregating some data from different sources within that community. That’d still be three separate PMs, but fewer places to go.
A step beyond that could be to use tools within AI personas to fetch data from across communities to build a single report from the data across them.
I think a lot of the building blocks are there and while using them to piece something together may seem like more work, it’s also an opportunity to build exactly what’s needed and prioritize which pieces are more important to put in place sooner vs. later.
And if they all prove valuable and more is desired, something more custom could then be built like a custom plugin with greater confidence that it’ll be delivering the desired outcomes.