That is a neat idea Brad62
How markers work though is that they in essence are counters too. We just don't draw the counter anymore, just the content so they appear as part of the map. This is true be it a wreck marker, IP marker what not. So what this means there can be only one marker counter at one hex at one time. At least until when we figure out an easy way to have more.
So while we have two wreck sets to indicate the density of wrecks (either one or two burning tanks), then we have the two individual sets of both, like the left and right facing single burning tanks, we at the moment can't draw a hex where there'd be one say "friendly" and one say "hostile" wreck marker at the same time.
For this reason we don't have different wreck markers for different unit types atm either, say APC, AFV, truck, (helo), they could all have different wreck markers if we would draw them in a manner they'd somehow overlap each other nicely should they all be drawn to same hex.