And as I always forget (getting old remember) how to have dhcpd configured to serve for multiple networks on one interface (e.g with aliases)
(as in test setups eg. ) I`ll write it down here, So next time google can point right back to me

1. shared-network thisismessy {
2. subnet 10.8.0.0 netmask 255.255.0.0 {
3. option routers 10.8.0.1;
4. }
5. subnet 10.12.0.0 netmask 255.255.0.0 {
6. option routers 10.12.0.1;
7. }
8. subnet 10.16.0.0 netmask 255.255.0.0 {
9. option routers 10.16.0.1;
10. }
11. }