Filtering vm's based on datastoreFolder

I can't find an easy way to filter vm's based on a datastore Folder.

For example I would like to do somthing like this

my $vm = Vim::find_entity_view(view_type => 'VirtualMachine', begin_entinty => $datacenter, filter => {'datastoreFolder().name => 'myFolder' } );

I know the bold isn't correct above, but I can't think of a concise way of doing this without finding the name datastore the vm is in, then next getting a datastore browser and getting the filter after that fact from there.

Basically I can't think of a clean way of doing this.  Any help would be greatly appreciated!