Hi,
While you can use targeted LDP to bring the session up, I dont think the labels will be used while egressing this interface.
An LDP speaker after establishing the LDP session will track all interfaces (to tht specific neighbor) for LDP hello. For example, if RouterA have multiple interfaces to RouterB with LDP session and if egress interface for prefixP from RouterA is interface1 which doesnt receive hello from RouterB, RouterA will not impose any labels. But if the egress is interface2 on which LDP hello is received, it will impose the label (received via the LDP session).
You may have to fix the 224.0.0.2 problem to have your labeling work. One ugly solution, I can quickly think of is to have a tunnel between the neighbors with LDP enabled on the tunnel and tweak the routing to have the (required) prefixes use the tunnel as egress interface. But IMHO, this is a good solution.
HTH,
Nagendra
