Automator and Exiftool

Hi. My intension is to write GPS data from a XMP file to and an JPG file (both file have the same name) for a number of XMP/JPS-file pairs.
In Terminal exiftool allows me to do this using:

exiftool -tagsfromfile Src.xmp "-all>gps:all" Dst.jpg

To avoid doing this hundreds of times I intended to set up an automator service.
So far I have managed to get the XMPs and JPGs stored in different variables by using two "Ask for Finder Item->Set Value to Variable" processes.
Using "Get Value of Variable" for both variables generates a stacked variable for the following "Run Shell Script". The point I am struggling with is how to tell my exiftool command with part of the variable to use.

My script so far is as simple as

Code:

for f in "$@"
do
exiftool -tagsfromfile "$@" "-all>gps:all" "$@"
done

I know that "$@" stores a list of the paths to both the XMPs and JPGs files (this is why the above script can not work). However I am struggling to tell the exiftool which part of this list to use in the right place.

Any advise is highly appreciated.