UNICAST problem after partition and subsequent merge

When we have 2 members A and B, and there is a partition, then there are 2 groups:

and

.
When there is a subsequent merge, due to http://jira.jboss.com/jira/browse/JGRP-145, A will discard unicast messages to B and vice versa.

We need to generally come up with an answer to whether unicast messages can only be sent to members, or to anyone, even outside the group.
For merge, e.g., we need to send a unicast MERGE_REQ message from A to B.