Site-to-Site VPN Tunnel Monitoring through NPM

So, I'm trying to monitor something odd and was wondering if anyone might have some insight as to the best way to do this.

 We have several vendors that use permanent site-to-site VPN tunnels to gain access to our network.  Long story short, the vendor controls the VPN side and we control the tunnel side through the use of ACLs that are removed to allow traffic to pass the tunnel and then replaced to prevent access.  These ACLs are located on layer 3 VLAN interfaces in our Cisco 6509 switches.

I need a way to monitor these tunnels through NPM so that our support groups can tell when the vendor tunnels are open.  Any thoughts?

We are running Orion NPM v9.0 SP2.

Thanks!