Dunno about the clever part.
Generally the info from the FAQ /t/967/1 apply.
So e.g. if you have artist and albumartist and want to append albumartist with artist then use an action of the type "Format tag field" for ALBUMARTIST
enter as formatstring:
%albumartist% %artist%
BTW: What is the "track name"? TITLE? Filename? TRACK? COMMENT?