How to merge a single layer to multiple other layers simultaneously?

I'm fairly new to gimp. I sometimes work on several hundred layers at a time. I am often trying to merge a single layer overtop of all of these others layers.

Like this example:

A

B

C

D

E

Merging into this

A+B

A+C

A+D

A+E

And so on. I have been manually copying layer A over and over, reordering them, and merging down one at a time. Is there a faster way to accomplish the same thing. I would love to be able to just pick a layer and merge it independently and simultaneously with multiple other layers.