I sounds like you just saved the static prop created by the grouping tool.

If your clothing figure does not quite fit the assigned figure but you are able to somehow edit its shape to fit you then need to proceed as follows.

Conform the shirt to the fully zeroed base figure.
File > Export > Wavefront OBJ (the shirt figure)
Select these export options:-
-- Weld body part seams
-- Include body part names in polygon groups

Save so as to overwrite the OBJ file that is currently being used by the shirt. (Suggest that you back up the original.

You can find out where the shirt OBJ file is by opening the shirt CR2 file in any text editor such as Notepad. The OBJ path will be in the line starting with "figureResFile"

Or you can save as a new file then edit the figureResFile lines in the CR2 file accordingly. Note that there will be two instances of the figureResFile line, you need to edit them both.

(I anticipate sending you a revised file later today.)