Concatenate 2D array of binary data


I have such a document:

	"_id" : ...
	"d" : [
			"h" : [ ]
			"h" : [

I want to update all document in a way, that I want to concatenate all binary array elements into 1 binary field, so the “d” property has only 1 BinData() value

Please note, that currently, this is an array of objects, but I think this was a bad design decision

Hi there, any idea regarding this problem?
Thank you