Hi.
I am working on Ubuntu 12.04 as host for Virtualbox VMs. In virtualbox I am running two Debian 6 DHCP servers for different networks.

Now, I want those two DHCP server virtual NICs to share one Physical NIC of my host, so that I can connect manageable switch (having VLANs) and connect client machines.

In BRIDGED NETWORKING, for both DHCP SERVERS
When I run my first DHCP server it gives as IP to physical NIC and if connect switch to that NIC, client PCs get IP.
But, when I start my 2nd DHCP server, both servers conflict (as expected) i.e. other DHCP wants to give IP address to the same Physical NIC.

How can I do this? Please Help!