How do I create one list/form that is identical to a subset of another list and automatically updated?

How do I create one list/form that is identical to a subset of another list and automatically updated?

I need to create one list/form (Form A) that is identical to a subset (based on values of multiple fields) of another, larger list/form (Form B) and is automatically updated periodically?
Also, I need to be able to identify when a change was made to a specific field in Form A.

Anyone have any good ideas on how to do this?

Thank you,
zzarda