Multiple Context ASIC (mASIC) is a circuit grouping a set of designs (applications) which operates at mutually exclusive times. In this paper we propose to take this particularity into account when we run logic synthesis. The idea is to maximize logic resources sharing between designs to reduce the total resulting area. Once used on mASIC for a set of 5 benchmark designs, our synthesizing technique reduces area by 28% compared to the sum of the 5 individual ASIC areas.