When I develop webstuff, I sometimes use a vagrant box for the development. This is how I use dnsmasq to resolve all domains ending with <insert tld here> to one and the same IP (be it your local IP or that of, in my case, a vagrant box).
First. Install dnsmasq.
# listen only to this IP
# file with dns servers
# resolve all .app tlds to this IP
Using this, you can use more than three servers (in Linux the max is 3, see /usr/include/resolv.h).
And finally use your dnsmasq server in your resolv.conf file.