Not that I know of, though don't quote me. I think the way to do it is use the nearestobject command to identify it immediately after it has been dropped.
Btw, if you think of an addition to your post after you have made it, it's better just to "modify" the original post. Keeps the thread cleaner and easier to read.
You could maybe do altitude by setpossing an invisible H to the ground underneath the bomb. Then use distance command to set the detonation height. I suspect a gamelogic or marker would be set to sea level, which is no good unless you use 0 for the height component of the setpos array.