This paper studies the scheduling of jobs of different families on parallel machines, where not all machines are qualified (eligible) to process all job families. Originating from semiconductor manufacturing, an important constraint imposes that the time between the processing of two consecutive jobs of the same family on a machine does not exceed a given time limit. Otherwise, the machine becomes disqualified for this family. The goal is to minimize both the flow time and the number of disqualifications of job families on machines. To solve this problem, an integer linear programming model and a constraint programming model are proposed, as well as two improvement procedures of existing heuristics: A Recursive Heuristic and a Simulated Annealing algorithm. Numerical experiments on randomly generated instances compare the performances of each method.