RosterBot now has an exceptionally powerful feature which allows team managers to define positions, assign those positions to players, and manage RSVPs on a per-position basis. Not only is this feature really cool and totally unique, but it’s very open-ended.
If you manage a hockey team (we promise not to use hockey as an example always) you can make this feature as discrete as you wish. For example, you can create two classes of player: “Skater” and “Goalie”; you can define “Forward”, “Defense”, and “Goalie”; or you can create discrete each individual position as “Left Defence”, “Right Defence”, “Center”, “Left Wing”, “Right Wing”, and of course “Goalie”.
Because this is a blog post, we’ll keep it simple, and just use “Skater” and “Goalie”. Head on over to the POSITIONS tab on your team’s page, and add two positions:
You’ve got to hit the ON switch before this will work. 
Remember to set real minimums and maximums for each position. When you’re done, skip back to the ROSTER tab and assign players to different positions.
From here, you can assign positions to individual members. Once they are assigned by Team Managers, only managers can manipulate the position of a player on a given team.
When players RSVP, they will begin to fill the positions you create and assign to them, until the maximum number of players for that position is met. If they attempt to RSVP for a position that is filled for the event, they will not be allowed to select “IN” for that event.
You can use this to simply differentiate your GOALIE from regular SKATERs on your hockey team, or if you are OCD you can create positions all the way down to LEFT DEFENSE, RIGHT DEFENSE, CENTER, LEFT WING, RIGHT WING, and of course WATER BOY. :)
This feature is still fairly BETA… be careful as it could omit players from your events if it’s not properly configured. We’d definitely like your feedback as we evolve it toward perfection.