I can't establish a relationship between the two tables because a unique key doesn't exist.
Sure you can. TableA::Company = TableB::Company
Then, in Table A, your calc field might be:
If (TableA::Company = TableB::Company ; "It's there!" ; "It isnt there !" )
If it isn't there, there will be no related records, so TableB::Company will not exist and cannot equal TableA::Company.
You rock big time!! Thanks for this response - I knew it was pretty straightforward but I couldn't get past the "unique key" thing. Thanks for the quick response and have a great weekend!