"I don't know if it's gym code or not, but i learned a lot from the higher belts, probably more so than from my instructors. Mostly because they are able to give you one on one time whereas the instructor is too spread thin. I wouldn't be shy to ask, you'll find that 99% of people that train bjj are very friendly and willing to help."
^^^ This. I found that I would stay with the other white belts. In this type of fish school of white belt comfort. Lately, I decided to roll with some of the higher belts and my game jumped. When you make a mistake they tell you why, when you do something good they tell you why. If you keep getting stuck in the same spot they tell you and help you work ways out of it. Many people will think a higher belt will just tap me over and over (and they do, but with it comes knowledge) and laugh, but most, I've found, treat you with respect and understand that you are learning because they were too.
Also, don't forget to roll with heavier guys if possible. Last night I rolled with a beast of a man...got smashed, but learned to concentrate on technique and not rely on strength as he out muscled me and treated me like Frodo without a ring to help me.