I am working on a project that involves multiple wikis. However, we want to control the way people sign up. They need to sign up for the main website first, and then only after they have done that can they sign up the rest (if they want to).

The way we can do this is to have a page on the main website that is only visible to site members, and put a ton of join links on there. However, we'd need to be able to define which site each one signs the user up for.

So I'd like the Join module to accept a 'site' or 'source' parameter (like the Clone module) that tells the button which site it corresponds to.

Of course, if there is a better way to achieve the same result, that would also be worth implementing.

We just don't want someone clicking on the join link of one of these secondary websites first, without having an account on the main one first.