Mapping Domain To Category?

I'm currently struggling to figure out a solution (or to even figure out if it is possible) for what I need to accomplish. We have a site located at... say... We could go the MS route, but would prefer to operate everything out of the same dashboard or same "site" (being the main site). We have categories that are using their own themes (child themes) and we would like to have some of them use their own domains.

In other words, instead of we would LOVE to be using but have this mapped to the category.

This way everything is fed in to the same "loop" even though it is fully accessible by multiple domains.

I found a couple of possible scenarios here.

But I'm thinking this will cause login problems. Does anyone have thoughts on this? And is there a way to customize .htaccess to make this work?

Thanks in advance.