Replacement supports accepting contract for delegated groups (13)

'groups' is the definition.
The answer is an example.

'replacement supports accepting contract for delegated' is the wordplay.
I cannot really see how this works, but
'replacement' could be 'sub' (substitute) and 'sub' is located in the answer.
'supports' could be 'tees' (tee is a kind of support) and 'tees' is located in the answer.
The remaining letters 'commit' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?