This 'server group' thing just sounds like a weird and (sorry...) stupid solution. Why are you reinventing the wheel here? If I want to buy or sell a rare item or group up with people or find a guild, I don't care in the slightest about people on other servers (as they are not my target audience for making a post) and it just seems really odd to do it this way. Server forums fix this problem. In fact, server forums have fixed this problem for years. Yeah, I can use the search function, but that doesn't really settle the issue for me, as you are still making it more difficult than it needs to be. Get it together Bioware! Whoever came up with this idea shouldn't be allowed to have ideas anymore...
I'm all for creative solutions, but this is just a really crappy way to solve this. In 6 months we will probably end up with server forums after you get a bunch of complaints, so just do it now, save yourself the trouble down the road, and stop wasting everyone's time with bad ideas. =/
Edit: Some other users also make a good point in that most posts in these server group forums likely won't have a server tag on them. This just makes the problem worse. Please, just fix it, add the server specific forums and let us move on...