Maybe I should divide the question into three more manageable parts:

1) How would a servant create a list of other servants who are currently online?

2) How would a servant send a message to another servant utilizing the p2p network?
(2.1: direct peer to peer connectons do seem difficult due to firewall / nat issues - don't they?)

3) How could 'broadcast groups' of servants be managed (like channels in IRC or peer groups in jxta)?