|Rodrik the Blunt|
|⦵ Walter Sheppard Regional Venture-Coordinator, Northwest aka WalterGM|
Given that this is PFS, having a RAW answer would be nice. Unfortunately, UE was released after the ARG and the fighter weapon group in that book still lacks longhammers. So getting a RAW on this might have to wait until some UE errata (or another book) comes out.
The good news, is that it isn't in the polearm group either. Given that it's just a long earth breaker, I doubt many GMs would give you a hard time for assuming it falls into the hammer weapon group as well.