[c-nsp] Router on a stick with multiple bridged interfaces

[Robert Johnson]

Hello Cisco experts,
Here's today's question. I have a simple router on a stick with a
fastethernet interface and multiple 802.1Q subinterfaces connected to a
layer 2 switchport in trunk mode. Now say I want to add another switch with
the same group of VLANs as the first switch, bridged to the first switch.
Instead of connecting the new switch to a trunk port on the existing switch,
I'd like to attach it to a router interface. So essentially I want two
router interfaces that are transparently bridged, with the ability to attach
routed 802.1Q subinterfaces to both interfaces simultaneously.

What's the best way to do this?

Robert