User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20031007
I thought source routing merely implied that a route might only be applicable
for certain source prefixes, not that there could be multiple routes
for a given destination address/prefix that get applied based on the source
address in the packet.
There are ways to do this, particularly with MPLS-TE. This allows for
redundant paths based on all sorts of criteria. But I don't think this
is what you had in mind.