Hey Mike,
Not sure what platform you're running BIRD on, but in Ubuntu/Linux, I use loopback interfaces to do this. Here is what my interfaces file / BIRD config look like. I am using /32s, but I don't think there are any issues with /24s going into BGP. Let me know if you have any questions or I missed your questions in some way.
/etc/network/interfaces:
# The loopback network interface
auto lo
iface lo inet loopback
auto lo:10
iface lo:10 inet static
address 172.22.150.126
netmask 255.255.255.255
auto lo:11
iface lo:11 inet static
address 172.27.255.29
netmask 255.255.255.255
auto lo:20
iface lo:20 inet static
address 172.22.150.119
netmask 255.255.255.255
bird.conf:
protocol direct {
interface "lo*";
}
/Charles van Niman