Routing in mobile ad-hoc networks is a challenging task. This paper proposes MPG-TAR, trust-aware routing protocol based on the formation of trusted Mobile Process groups (MPG). MPG is a collection of processes or mobile nodes present in defined vicinity where they all lie within each other's radio transmission range. The trusted MPG groups formed in MPG-TAR calculate trust based on the mobility rate, membership time within a local group and the number of overlapping groups of a node. The proposed protocol continuously computes and updates the reliability, trustworthiness of a node and finds the confidence level in that node. If the node is trustworthy and reliable, the confidence in that node will be increased to trust the node for forwarding a data packet. Simulation of MPG-TAR was done using Glomosim simulator.