This afternoon, the stars aligned for Bar and me to have a test with other horses and riders in the arena, so we did it and he was awesome.
Katie was already going to ride and one of the other boarders and her boyfriend were there riding two of the mares Bar knows from the big pasture. (They hang out by his paddock all the time and he's quite fond of them.)
Since the two folks besides Katie are good, relaxed horse people, I went ahead and saddled Bar and went down to the arena. Everyone else was already here, and he stayed quiet as we went inside, just eyeballing the various bodies with a slightly worried look. I had him work at a slow trot inside the round pen first (our round pen is at one end of the indoor arena), quietly talking to him and keeping him focused on what we were doing, not what was going on around him.
He was attentive and cooperative, so we moved out into the arena with everyone else. I wasn't really interested in giving him a hard workout, mainly just keeping him on task and relaxed with other horses and riders around him. This is as much for me as for him since (as I've mentioned before) I do tend to tense up with others in the arena.
At first, he kept trying to get close to the other horses, but we just redirected his energies and did obstacles until he settled down and just walked the arena with me. We did try to walk next to Katie and Sammy, but Sammy turned around and snapped at Bar, so we backed off of that for now.
Once the other two riders left, I had Bar trot around the outside of the round pen while Katie trotted Sammy around the whole arena. The work around the round pen helps him bend, and having Sammy come up behind him and me insist he maintain discipline was also good. For both of us.
We'll ease into harder work with other riders around, but I was really pleased with his behavior today. There was only one time I could feel him start to go--he makes this funny noise, you see--kind of like a muffled, frustrated, squeal in his throat. Katie and Sammy were trotting up behind us, he started to bunch up under me and there came that noise. I just waggled the reins and warned him not to go there and he subsided from the edge like a well-poured beer.
My goal was to treat this as a situation where he could be relaxed and responsive to his rider, even if he wanted to go socialize, and he did a great job. Maybe it seems like baby steps, but I'll take it as a win anyway.