Q: Is there any way to merge collections together?
A: Actually, there is a way to merge collections together manually. It is possible if you open both of them up in a text editor and just copy and paste one into the other. However, if there are duplicates on the list, the app will only pick up one of the entries, so try to go over the list before you import it to look for duplicates.
Note: please backup both of the collection files before doing this.