yes.
right now, people only see the forums that they are allowed to participate in.
you probably want a filter to go further than that and limit them to only one specific one.
i can see changing it to say, only provide feeds for forums that are a specific category "Rss feeds"... or something like that.
i don't really plan to modify the current feeder for this version (6.4) though. when 6.5 comes out, i will probably give it an overhaul and put in more flexibility, like you are requesting
