I have a real interface en0 with its MAC and IP addresses.

I want to create a virtual (pseudo) interface, say vx0, such that:
1. vx0 has the same MAC address as en0,
2. vx0 can have an independently assigned static IP address
3. For all IP packets received on en0, if their destination IP address is that of vx0, then these packets must be 
forwarded to vx0, and the receive function of vx0 must be the same as that of en0.
4. For all packets to be sent out via vx0, the source IP address must be the address of vx0 interface. And these packets
 must be physically sent out from en0.

I can create a virtual interface via the ioctl call SIOCIFCREATE. But only interfaces of type VLAN, GRE or GIF can be 
created. I want none of these. Can such a virtual interface be created?

Thanks.