The usual way to do that with software might be the Gnu license (GPL) i.e. “you can use this open source software but if you do then your software which you use this with must be or become open source too”, also the newer Affero license.
I’ve never heard of licensing e.g. the functional specs though, can’t guess what it means in practice.
Perhaps I’m wrong, IANAL, my understanding is that your restrictive license is restrictive if or to the extent that you’re willing to go to court to protect it, which you’re not, because doing that is expensive – like having a patent portfolio, it’s a game for bigger fish.
So “protecting our community” means only that you try to ensure that Ty Coon doesn’t sue our community for violating one of their licenses.
A GPL license can be used to try to “poison the well” (and to benefit from changes other people make) – in theory – a commercial company won’t want to touch stuff licensed with GPL because their touching would will open-source their software, which they might want to keep closed.
That’s a different matter, i.e. trademark, and whether the public can tell whether the two things are different (e.g. different name and logo and “trade dress”).