How to add local configuration to the dnsmasq in 12.04?

[Chris Green]

Ubuntu 12.04 now uses dnsmasq as a local DNS, it gets run by Network
Manager. 

Up to 12.04 I had my own dnsmasq installation for managing my LAN, it
provides local name services and DHCP.

How can I merge my dnsmasq configuration into the Network Manager one so
that it is kept through upgrades etc.?  Is there a 'proper' way to do
this? 

I know I can simply disable the Network Manager dnsmasq and run my own
but that seems a decidedly clumsy way to to it.

-- 
Chris Green