lists and dropdowns

I know how to make a dropdown combo box and link it to a list. My question is, how can I make it so an item on the list can only be used once.
Here's my example:
Say I want to make a table where four people are choosing players for a team. Each person gets to choose 10 players from a list of 50 names. Each cell in the table will have a dropdown linked to this list. Once a name is chosen, it needs to be hidden from the list so that it cannot be chosen again.
Is this possible?
Thank you

Thanks to you and JB.
The way I understand it, a number, "key", was assigned to each name and that was used to to create the formula guiding the list. Very good!
This should work just fine.
Thanks again!