Yes, if there's a DISboards Fish Extender group set up, it would start here. Other sites may also have FE groups, but they are not DISboards connected.
It's a little early to start setting up a group just yet. Typically 6-8 months out is a good time to get things going. Before that, unfortunately, you'll find people who, when flush with the "I've just booked a
Disney cruise" excitement, will say "I want to participate" and then you never hear from them again. This could be because of changing circumstances or change of heart and they cancel the cruise. Or they figure out there's a little more involved with it than they thought. Then you're left with a FE list full of holes (people no longer around, and un-contactable).
Until then, you can use this thread to discuss all the other things involved with taking your cruise.