Implement probabilistic broadcast

Dear all,
I am a new NS-2 user. I wanted to implement probabilistic broadcast
scheme for MANET specially for AODV routing algorithm.
To explain my problem: when any nod want to find path or rout, it broadcast RREQ message for it’s all
neighbors,I want to add a probability, so the RREQ message will send for such a probability.

for example if number of neighbor for x nod is equal 10,the RREQ message will send 10 times.

if the probability p = 0.5, then the RREQ message will send 10 * 0.5 = 5.

pleas can you help me .

best regards.