What algorithm is appropriate for finding possible matches to form a group of L players?

Multi tool use
What algorithm is appropriate for finding possible matches to form a group of L players?
Given a group of M1, M2, ... , Mn teams (each team has length <= L/2) I am trying to find (as efficiently as possible, iteratively) combinations which match the criteria:
Note:
Any pointers, links, hints appreciated.
@Dai Agreed. I have edited to indicate I can work with a stream of results as well.
– kidoman
Jul 1 at 20:16
I've deleted my answer as it is not a good fit given the additional note above.
– chucksmash
Jul 1 at 21:03
You can probably solve this using max flow
– juvian
Jul 2 at 15:35
@juvian could u expand on what you said?
– kidoman
Jul 4 at 22:43
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"all possible combinations" - that sounds expensive.
– Dai
Jul 1 at 19:15