It's possible but only for one album/directory because there's no way to reset the counter
This pads the tracknumbers always with two digits ##/##
Action type: Format value
Field: TRACK
Format string: $num(%_counter%,2)/$num(%_total_files%,2)
This pads depending on the total amount of files i.e. 1/8 or 01/15 or 089/112
Action type: Format value
Field: TRACK
Forma tstring: $num(%_counter%,$len(%_total_files%))/$num(%_total_files%,$len(%_total_files%))