PXE: different boot images for different MAC addresses

I have configured an OpenWrt host to allow other hosts on the network to boot using PXE. This involved configuring TFTP and DHCP. Due to the range of hosts, I would like to provide different boot images depending on the MAC address of the client. However, I have not yet found an example that does this. Is this possible, using dnsmasq?

I found a feature in dnsmasq that supports this, and I proposed adding support to OpenWrt. See https://github.com/openwrt/openwrt/pull/3453.