Multiple router IDs

[William]

Hi all,
I'm wondering if there's a way to present a different router ID to 
different BGP (or other) peers?

I can't see a way of doing it unless the "router id from <interface 
mask>" provides the solution but it's still a global option.  Quagga had 
that function as part of its BGP multiple-instance mode, and for what 
I'm investigating, would be useful tool.

Regards,
William