Thanks for the quick responses i did try your plugin, it is excellent but it seems to bring back slightly different values from what is in Artists and would require further manipulation to correct.
I used $setmulti(Guest Artist,%_artists_track_additional_std%)
Results on this track:
Title: 1st & 10 (feat. Infamous 2-0 & Fate Wilson)
Artists: Ludacris; Infamous 2-0; Fate Wilson
Guest Artist: I-20 & Fate Wilson
Thats why i was keen to take all artists after the first from %Artists% so i know the results come back consistent
EDIT also tried _artists_track_additional_cred but comes up with the same result. Note the different spelling of artists in Guest Artist and no multi-value ;