What does a "roster" mean in this case? A group of players that play together (analogous to a "team")? Just wondering so that I know what I'm talking about here.
and while I'm at it, what does "Special Groupings" even mean in everyday pedestrian English? First things first when describing database tables and objects - use the most obvious everyday words for column and table names. Nobody wants to spend all day guessing what your names mean. is "Special Groupings" like a team or something?