Resource availability in pervasive environments is restricted by many either mobility- and/or security-related factors. Multi-agent systems deployed in such environments would have to rely on a potentially low number of hosts allowing and supporting the arrival and execution of foreign code. To address this issue, this paper proposes to decouple interaction of executing programs and services from the actual software mobility pattern used to realize this interaction. The proposed system (MoDeS - Mobility Decision System) dynamically decides on the best mobility method to implement a series of software interactions while satisfying the appropriate software constraints. The system takes as input an interaction plan and produces the corresponding mobility plan. A series of simulations were performed on single- and multi-hop scenarios which showed that MoDeS can significantly increase the availability of software interactions even in highly constraint environments.