$Groupcount

$Groupcount is a conditional mask tool that can be used to change the art summary field based on how many tracks are grouped together in a particular sorting of tracks.

$groupcount represents the number of files in an Album/Series given the current sort (i.e. it isn't the absolute number of files in an Album or Series, but rather the number of files that in an Album/Series that are adjacent to one another given the current View/Sort)

Summary masks would use something like: $if($groupcount=1,{mask for 1 file},{mask for >1 file})