PIX in multiple IPsec roles

Is there a plausible way to convince a PIX to pass through an
IPsec tunnel to another device while simultaneously being an
endpoint for a different tunnel?

I have sites A, B, and C. Each has a PIX515E with tunnels to the
other two sites.

Now a vendor wants to establish a tunnel to a device inside
PIX A. I seem to be lacking the right keywords to search for
this.

-dsr-


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