Well, first let mention, that our intention would be to try to simplify the UI, as it already might look for some users quite complex. Currently, it's possible to archive it easily by using two Forest object, but we'll evaluate your suggestion.
Regarding the multiple selection of Forest objects within Forest Lister - we totally agree. Actually, it's already on our wish-list and we'll try to implement it in future releases.
Thanks a lot for your suggestions, your feedback is very important to us.