Check the pop-up menu in the Hotlink Manager window, it allows you/forces you to decide if you want to select either PLNs or MODs (the unchosen will be grayed).
If you can have two copies of ArchiCAD open, you can import every unit once into a 'library' file and just copy-paste the modules into the main file as you need them --much smoother than clumsy Hotlink Manager.
Are you finding any advantage in using MODs instead of PLNs? My sense is that as they don't carry views, all layers, and other template information, PLNs give you a lot more flexibility if you need to edit them.
