Cross Referencing

Apologies if this seems a simple question, but I am at a bit of a loss
on how to do it.

I have two lists of people with a many to many relationship Group A
work with number of people from Group B and the people from Group B
can work with multiple members of Group A.

How can I create a document using one list for Group A and Group B and
use functions, etc to combine them in both forms (to list all the
Group A people working with an individual Group B person and visa
versa).

Any help would be greatly appreciated.