variables – ExifTool need to find name of the first file in sequence

I am using third party image viewer (XnView) that allows to select files i want and then run ExifTool with custom command line on this files only.

When i open multiple files using ExifTool i get name of each file using ${FileName}.

However i need to find name of only first file from all files selected, because i need to create folder with name of first file in sequence then move all files there.

-k -Filename<${Directory}\${FileName;s/\.[^.]*$//}\${Filename} – this moves each file to separate folder, need to move all files to one folder

Is there way to get file names array so i can then query first entry e.g. filesArray[1] or how can i get name of first file?