Before I outline a possible solution does your VMware Workstation host machine have two physical ethernet adapters — one for the connection to the existing router and the other for the connection to the rest of the network. (If you only have one physical ethernet adapter you are limited to the host machine.) You will also need to reconfigure the physical connections for the other devices on your network so their traffic flows via the host machine.
It will also be helpful to know the host operating system and the version of Workstation you are planning to use.