If they are small modules (say balconies, bathrooms, unit plans) it makes sense to bring them all once into a pln file to be used as a 'module library' in a second session of ArchiCAD. With Suspend Groups unchecked you can copy paste the modules into your destination file as you need them, and also you have immediate feedback as to the state of your whole modules package (such as when you make changes to some unit plan and have not updated some other yet).
