Sorry to threadjack but I have the same question; flights from LPA-LIS-EWR on TAP (executive class) booked on one ticket, then EWR-ATL on UA (first class) on a separate ticket. Baggage allowances are the same. While I know that TAP is not required to check baggage through to my final destination I wonder how experienced and flexible TAP agents are about interlining baggage on another Star Alliance carrier ticketed separately.

(I know I'd need to claim them and go through customs in EWR but it would be convenient to be able to just drop them at the baggage recheck area just outside customs instead of going to the terminal check-in counters to recheck them).