There isn't a very tight knit community in the Denver area (not the rest of CO) when it comes to the Supra. The closer you get to the coast the bigger the groups you find... I suspect this is largely due to those areas having had the greatest number sold.
Check out the Toyota/Lexus annual owner's meet which is held in Castle Rock, you're going to see the biggest turn out there.
Haven't had a MKIII for a while now, but "Hi" from a former MKIII owner.