How to merge cards not in mindmaps

Hello, I was wondering if it is possible to merge cards that aren’t in the mindmap. I don’t want to add these specific cards in the mindmap but would like to unmerge and remerge them from the sidebar.

I’ve been trying to figure out if this is possible but it doesn’t seem so.

Hello. I’m curious as to why you need to modify these cards without adding them to the mind map. This might indicate that we haven’t fully understood your usage pattern before. Could you briefly tell me about your workflow and the role of this feature within it? In this way, I can provide you with better suggestions.

Hello, I have documents that contain questions that I can use to practice for exams. I make these into review cards but do not put them in the mindmap as it would be redundant in my notes (and also cause it to look too messy). I occasionally makes mistakes in which cards should be together and instead of redoing my highlights, would like to merge it and unmerge it from the card/review panel but there is no easy way to do this.