MikroTik VPN With Multiple External IP Addresses

I have a MikroTik CCR1009-8G-1S that is providing the Internet connection for two separate but co-located businesses. Both businesses have VPN configured on their servers and the MikroTik passes the traffic from a specific external IP to the appropriate internal server. What I want to do is enable VPN on the MikroTik itself for the third external IP but, so far, my tests (I have a second unit for testing) cause the VPN to bind to all external IPs.

Current Arrangement: (IPs are example only)

External IP
10.10.10.1 -> VPN pass through to business 1 server
10.10.10.2 -> VPN pass through to business 2 server
10.10.10.3 -> Not currently in use.

I want to use the same VPN ports on 10.10.10.3 with the built in MikroTik VPN server without interfering with those port on the other 2 IPs.

I have VPN working (I don’t need help with that configuration) but it’s either pass through on all external IPs or built in MikroTik VPN on all external IPs.

Any ideas on how to getting it working with both VPN systems?