Tambone did a lot of business with the other families, and was known to grease the wheels. That is why Castellano brought up the matter with the Commission, cause even though he was a soldier in the Gambino family and Paul had the right to order him killed, doing so without notifying the other families that Tambone was heavy with would result in a lot of headaches, and Castellano would have to honor Tambone commitments in joint businesses with the other families. Remember by this time, Castellano became greedy with money, and he didnt want to give away money if he didn't have to. Gotti took Tambone off the shelf since Pete was a mentor to some of the Bergin crew, and it is possible that Tambone may have been part of Gaggi crew, but he was tight with 5 Gambino crews, plus with Christy Tic, Gennaro Langella, Alphonse Persico, and was close to the French Connection crew.