1-Some men who might be involved with the crime syndicate are being held for questioning.

The way I see thing there are three distinct possibilities:
a-Maybe they are all involved
b-Maybe some are involved
c-Maybe none is involved

I feel there is some ambiguity in 1, in that it is not clear if we are talking about the involvement of those men as a group or about the involvement of those men as distinct individuals.

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2-A group of men who might be involved with the crime syndicate is being held for questioning.

I think here we have two distinct possibilities:
d-Maybe the group is involved
e-Maybe the group is not involved


But if the verb is changed from 'is' to 'are', we will still have the same ambiguity as in '1'.

Is that correct?

Gratefully,
Navi.