Hole Series

I am trying to create a hole series through parts that are indifferent subassemblies. I have had lots of success creating holeseries through parts that are in the same assembly but I don't seeanywhere in the help section that says anything about parts indifferent subassemblies. When I try to select the other part (in adifferent subassembly) I get a warning message that says thesurface is not valid for that type of operation. Does anyone knowif this is possible?SolidworksAssemblies