Local Multicast Deployment
To minimize network complexity, would it be possible to "unicast" an image to a single master computer on a subnet, and have that master broadcast to remainder of the clients on that subnet?
This sort of already works this way. You can setup a new com server in that other subnet, the image is uploaded to it, and then it can multicast in that subnet from that com server. May not be exactly what you are thinking, but accomplishes the same goal.