Prevent sort from sorting filenames instead of greped content

In a script, I want to get a variable from find grep and sort to display it with echo on screen. The variable looks like:

OUTPUT="$(find . -maxdepth 2 -type f -name 'filename' | xargs grep -o -m 1 "string" | sort -r)"

Find should search for some files with the same name in folder xyz.Pipe them to grep to search these files for every first matching string in it.Then sort should sort descending.

This works pretty well except of no matter what I try sort will always sort by the filenames but it should sort by the matching strings grep has found.This is what the output looks like

/file3:111/file2:666/file1:333

And this is what I wanted echo to display no matter what the filename is:

 /file2:666 /file1:333 /file3:111

With grep -h I get the result I want but I also need the filenames to be displayed as additional info.