Is there a way, by map or device, to send probes from an alternative interface on the intermapper server?

My specific scenario is using ping tests from a single intermapper server out of multiple network interfaces connected to different points in my network.

I am attempting to track ping times, primarily to the internet, from the different layers of my firewall architecture, to track the latency the firewalls incur.  What I need to do is what linux ping does with the -b option, it binds to a specified interface instead of using the normal routing table.

The reason I need to do this is I need to send pings to one IP address from multiple places so there is a valid basis for comparison.

It is sort of the opposite of directly attaching a subnet to an interface to avoid routing the probes, which I already do for my management network.  I that case the normal routing table works as intended and automatically sends probe for the attached subnet out the correct interface.