I am trying to figure out how to take several records returned from a many-to-many relationship and create a single row.

Here is what I mean...

In my database, I have this relationship...
member -||----|<- private_msg ->|----||- private message
When a Sender sends a PM to multiple Recipients, there is one private_msg record, and there are several private_msg_recipient records.

So in my query, I would get something like this...

pm_id	username_to	subject		created_on
------	------------	--------	-----------
3	JustAmy		Baby Pics!!	2013-12-06
3	LisaLisa	Baby Pics!!	2013-12-06
3	GoGina		Baby Pics!!	2013-12-06
3	MissMarcy	Baby Pics!!	2013-12-06

But since the Sender only sent *one* Private Message, in the Sender's "Sent" folder, they should see something like this...

To				Subject		Date
---				--------	-----
JustyAmy, LisaLisa, GoGina...	Baby Pics!!	2013-12-06

For some reason, I'm drawing a blank on how to take multiple returned records and collapse them down into a single entry...