I do something similar to this at my high school. During lunch and opens, a few of us will get together and just practice individually, but listen to each other and advise each other on playing techniques. Usually it's a clarinet player, a tuba player, 2 trombone players, a flute, and a few saxers. Very informative because each player tends to focus on one section of playing as is required by the instrument, so if you approach the sessions right you can pick up a literal ton of information quickly.
Consiquently we all play extremely well together in ensambles, because we're so used to each other's styles and sounds.
This is obviously far from regular lessons, but I can pledge that such methods are extremely helpful, atleast in my humble and youthful oppinion
Excellent thread!