I find in groups/trips it's best, as Dr Bill and others noted, to pretty much stay in front or way in back. I've had a shooter, video, dive right into a WA shot I was taking a shot. Just zoomed in right up my back then blocking the pic... I hit him in the leg... DOH!!!.. just what are they thinking..
Another one, a diver thought it was kewl to swim underneath me, intentionally, with a great photo of bubbles as they past in front of the lens on my National Geographic Cover Photos (joking here, I wish??)
The point I'm trying to make is that you pretty much have to stay AWAY from the other divers, find your nitch and let them be. If you have a DM that found a seahorse or something, then you have to decide how important the shot is, and either get there first by following the DM - since they know all the hot spots - or doing something else until everyone has cleared the area... and typically the subject as fled in terror...
Most of the time I like getting diver shots of divers doing diver things.. so it's automatically AWAY from them. I typically dive as a 3rd in a buddy system. I'm there if they are having problems, but off on my own for the most part.
When diving locally, my dive buddy will follow me so as not to stir things up.. then proudly declare ALL the stuff I missed seeing... Octos, Orcas, Subs etc... heheh.. we're just two "Solo Divers" diving together... lotsa space...
Some people are just plan "Rude" and self absorbed, just like drivers on the freeways... just get outta their way and let them through... as maddening as that is...
Or you could just "Be at One... With the Backscatter/Silt" and learn to love it.. .heheh... in Dec, I've found, backscatter/silt looks like snow.. how kewl is that eh??
Hope that helps...???