Group membership is a fundamental building block that facilitates the development of fault-tolerant systems. The specification of group membership in partitionable systems has not yet reached the same level of maturity as in primary partition systems. Existing specifications do not satisfy the following two antagonistic requirements: (i) the specification must be weak enough to be solvable (implementable); (ii) it must be strong enough to simplify the design of fault-tolerant distributed applications in partitionable systems. In this article, we propose: (1) a new distributed system model that takes into account the formation of dynamic paths, (2) a specification of partitionable group membership for MANETS called PGM, and (3) an implementation of PGM designed by adapting a well-known solution of primary partition group membership, namely Paxos. This results in the specification of an abortable consensus as the combination of two abstractions: an eventual α partition-participant detector and an eventual register per partition that guarantee liveness and safety per partition, respectively. Then, partitionable group membership is solved by transformation into a sequence of abortable consensus.