Is this even possible ?
How could a network printer be shared between the 2 LANs ?
Would it create routing problems if one of the LANs becomes part of an AD / DFS on another site so that users can logon at either site and access files.
One LAN, 2 business units. 2 business units become 2 legal entities needing full network separation for compliance but want to continue to share cabling, patch panel and the costs of a single hi speed intenet connection - and possibly 1 leased MFP. All clients, servers, and all but 1 printer will be on one of the 2 LANs. One of the LANs will need to become part of an AD with computers on a remote sites LAN so will need a Site2Site VPN