i dont know any "simple" and "straight" way to do that...
may you should get a look at
http://www.wowwiki.com
if you search for the Event "FRIENDLIST_UPDATE", you will see: its fired many, many times...
Your friendlist could be scanned with
these functions. - same for
ignore
and your raid could be scanned too.
check for the event "RAID_ROSTER_UPDATE". (but beware, this event would be triggered many, many times too... so you may get some performance-issues)
and your "own ignore list"... maybe you're looking for
ExtraExtendedIgnore