John Giovannitti, 61, the mayor-elect in Paulsboro, and Vince Giovannitti, 57, the newly reelected mayor of Gibbstown, are brothers. The relationship is fitting, because the two New Jersey towns — which the Giovannittis describe as “joined at the hip” — are basically brothers themselves. The third-generation Paulsboro brothers can expect to collaborate as mayors of neighboring towns that share certain services, and being siblings just makes it easier. “We can say things to one another,” Vince said, admitting he may be more reserved with somebody else. Inevitably seeing each other at family fun…