I have about 7 mindmaps that have things in common. However, I will like to come up with one mindmap by merging these maps together to show where ideas and concepts in the individual are using that merged map. Thanks.
Have you asked the vendor of the product(s) you use or posted this question to a user community of the product (if one exists)?
One thing that comes to mind (pardon the pun) is to make a mindmap of your mindmaps. I realize this doesn't answer your question about merging them, but in the absence of being able to, this might be a good work around.