KDC acting as both master and slave

I am trying to set up a chain of KDCs where KDC1 replicates from KDC2 
and KDC2 replicates from KDC3.

Thus, KDC2 is both a master and slave.

However, I cannot get this to work. If iprop-slave is running on KDC2, 
then KDC1 will not replicate from KDC2. As soon as I stop the 
iprop-slave process, KDC1 starts replicating.

Is it possible to have a Heimdal KDC act as both a master and slave? If 
so, how?

Thanks, Adam Lewenberg