The following blogpost will help you to configure the EdgeRouter DHCPv6 server (dnsmasq) to resolve IPv6 and IPv4 addresses.
You can configure Dnsmasq with the the ra-nmes option to solve this issue.
The following config example may help you to configure it.
Note: Maybe you have to change the interface behind constructor.
For more information check out the man page from Dnsmasq.