Select files by type group or description

Hi all:
I am tryiing to limit the "changes" made. Since I am always finding files which are text, but the extention is not the usual. I find it easier to create a file group or associate the file to a program once. Pretty basic. Is there a way to have The Opus select/rename/delete etc based on the group file type, description.

I think I have seen this some where but I can not find the reference.

Thanks...

D-

I'm not completely sure what you want to do here. Could you give an example?