Is it possible to create a virtual machine that uses a different ethernet connection than the physical machine is using? If so, how would I accomplish this?
I am stlil not sure what your goal is, so I assume you want to have two NICs in your PC - one for host OS, one for VM.
In VirtualBox - when you define a VM, in network settings you define how virtual NIC is connected. One of the options is to use real NIC.