all/each/every

English as a Second Language English Vocabulary, Grammar and Idioms
1

[color=red]1-I am working with all of them.
2-I am working with every one of them.
3-I am working with each of them.

i think in all three sentences it is possible that I am working with each of them individually.
But if we are all working as a single group, then only “1” can be used.

Am I correct?

2

Yes, that seems reasonable.

3

“I am working with all of them as a single group.”
Is this sentence OK?

4

Yes.

However, unless there was some reason to emphasise “all” and “single”, one would normally just say “I am working with them as a group”.