If the stacks each get transport layer copies of what's incoming and the hidden stack gets to also see all that is outgoing and produce its own frames, it shoul

If the stacks each get transport layer copies of what's incoming and the hidden stack gets to also see all that is outgoing and produce its own frames, it should not be hard, and I think that's the level of interference we should assume at least. The hidden stack could listen in on DHCP communication to figure out what address to assume and act on any incoming packets as necessary, and until it actually sends something it would be invisible to your network. When it does send something it could then easily be with one of the addresses assigned to the non-hidden stack. It is not much different in concept from a normal layer 1 switch. Everything gets repeated and the recipients discard what they're not interested in.