by AndyDufresne on Sat Sep 04, 2010 4:29 pm
Ahoy Squirly,
Forum Modifications are usually not something we do---so we'll point you over to the phpBB Forum where developers work on the phpBB forum package and other modifications.
However, have you tried this? When viewing a PM with multiple recipients---click the 'Reply to sender and all recipients' link...this will create a new PM with the designated users populated in the sender list. Then scroll to the 'message history' below the text entry area for the PM, and click on any of the desired 'Quotes' from past messages, and they will populate your new PM.
Does that fill the need of what you are looking for?
--Andy