VM1 ---> Layer2 Device ---> VM2 + VM3 + .....+ VMn

I'm looking for help on this above given scenario.

The Layer2 device is supposed to be present in an inline mode so that it can filter the traffic ( based on criteria ) where the traffic will be landing on VM1 and then it will be forwarded to other VMs but the traffic will be caputred at Layer 2 by the external Layer2 device sitting outside the OpenStack setup ( can be connected to the OpenStack setup using additional NICs )

plus some other questions.

Note: this is a complete KILO OpenStack setup running on 3 nodes ( VM nodes from ESXi Server ) and works perfectly nice with default configuration using gre as tenant network types with OVS ( from docs.openstack.org for KILO )