Any kind of linking between GMRS and Amateur radio is expressly forbidden by the FCC and not supported or condoned by the HamVoIP project. As far as I know, GMRS users have developed and maintain their own lookup system using downloaded rpt_extnode style nodelists, not DNS.
I am curious what node numbers the GMRS traffic was coming from, so I can keep a lookout for this as well?
73, David KB4FXC