I'm looking for a small utility that will generate a list of all
possible combinations.  For example:

I have item A. (There will be multiple items, a B, C, D, etc)
Item A has subitems 1, 2, 3, etc.
There could be sub-sub-items under that, blue, pink, yellow, etc.

What I want is something that will automatically generate a list of
possible combinations. Let's say I want to compare A1 to everyother
possible item.  That would generate a list of records pairing A1 with
everything else.

What makes this more complicated is that I could have several items
specified (A1/B2, compared with everything else, etc), and the order
they are specified in could be important, and I don't want duplicates
in the list.

A plug in or Excel function, or a standalone utility is fine.

Please let me know if this doesn't sound clear.  Thanks!