It’s a hack but:
- Make group
- Select automatic enrolment via email domains
- Find the most popular email sign-ups to your site then add them all, the top 10 will account for like 95% of registrants
- Use/modify the in/out group script here to find people who fall through the gaps hwoever you want to slice it.
The easier way to probably achieve what you want is have trust level 0 (brand new) people climb to level 1 after reading 10 posts inside a visible “intro/welcome to the site” topic, make the rest of the site require trust level 1 then you can kick people you don’t like to level 0 or suspend them.
It’s been mentioned a few times about the site to have wildcard domain enrolment or similar but it needs a plug in, we could do with it to be honest…