Redundancy for Multicast (on Financial Environment)

I'm having a hard time trying to achieve a multicast redundancy on a very simple topology (which is attached). When the primary link on Router A fails to the feed source, multicast traffic is converged to backup link on Router B - which is a desired behavior. But after coming back, the traffic is not "preempted" by Router A. Even worse, if the link on Router B fails the traffic ceases to flow.

I'd appreciate if anyone could give me a help.

Thanks in advance.