Abstract-- This paper presents a proposal for group membership and access control services for JXTA, both based on the principle of self-organization and collaboration of peer group members. The need for collaboration strengthens the resistance against free riding and eases management of revocation data. The proposal prioritizes group autonomy and makes use of the concepts of web of trust and small world phenomenon in order to achieve its ends, distancing itself from approaches based on centralized PKI models or trusted third parties external to the group. It also offers an alternative to the basic group membership services distributed with the JXTA platform implementations.