Sharing Virtual MAC

Hi

We have dedicated (our) firewalls on all our hosts, using a failover IP and a virtual MAC dedicated to the firewall. We now have a scenario where we want a service to be bound to its own NAT IP.

Where we have hardware with a block of IPs assigned we would just add a virtual IP from the block to the firewall and go from there. In the OVH scenario with additional IPs (in addition to the existing failover IP) can we share the existing Virtual MAC, which would allow us to use virtual IPs as normal or must we create a new Virtual MAC and therefore an additional interface on the firewall?

The management interface shows the option to use an existing Virtual MAC but it's not documented whether that is moving it from the IP it's currently assigned to or sharing it.