Can I base access to a forum dependent on the referral url?

I have a few Hugo sites.

I want to keep them very simple but I would like to allow for coments and dicsussion.

I have set up a Discourse install on DigitalOcean.

I have
-> Hugo Site 1
-> Hugo Site 2

And I have categories
-> Forum for Huge Site 1
-> Forum for Huge Site 2.

I would like visitors from Hugo Site 1 based on the referral URL to be directed to Forum for Hugo Site 1. I would also like for users from one forum to see the other sites forum?

I would guess the way to do this is a separate Discourse install for both.
Presumably, that would mean quite a bit bigger droplet or more droplets
all of which would increase expenses.