how to have certain users see parts of the forum based on what link they click

[mchaos]

Ok, heres what I want to do. I have Ideas, I know I can get it to work, just wanted to here some other ppls advice.

I want to have a main page on my forum, with links, and depending on what link they enter the forum through, and or what theme they use, determines what forums they can see.

I will most likely be using cookies.

For instance..

On the front page, a link for dog lovers, and a link for cat lovers(this has nothing to do with my forum LoL, just an example) and if a user click cat lovers, they don't see the forum for dog lovers, but see cat lovers. and if they click dog lovers, they don't see cat lovers forum, but can see dog lovers.

as well, if they had the say, cat theme on, then they would see the cat lovers forum, nothing dog related.

Any one have any ideas on how to do this??

I have a bunch. I was thinking, use cookies and if statements. if any one knows an easyer way, hook it up. I was also thinking about using publicly joinable groups, but I wouldn't know how to make it changable by link.

Any one can help, that would be awesome...

Thanx...