all possibilities are listed in my previous post. pls read carefully the Dnsmasq's manpage excerpt I included there. The next thing I would try is putting the same content in /etc/hosts. But as I said before since DHCP isn't handled by dnsmasq by default in EdgeOS. None of the possibilies said in the manpage might work as a result.
Worth trying some of those. It's quick test anyway. Good luck.