Garbage In, Garbage Out.

I must apologize for wasting your time & not supplying representative data originally, so your solution worked based on what I posted earlier, but now i realize that many "families" of data do not have NULL dates. :blush:

Also, the MemID records are not sequential for a "family" of records. They are intermingled, so I made 1 group odd numbers, and one even numbers

So I've updated my original post.