Multi instance pgsql

Hi,

I'm experiencing problems for an environment with two postgresql 9.3 instances in a hot standby mode.

I am able to setup each of them stand alone (each instance has its own port and virtual IP) but when I try to setup both at the same time (the two master in the same node or in different one) only one of them starts properly (I mean that starts both nodes and synchronize them via streaming).

Does any of you have test that? Do you have a simple guide or any trick I must take care?

Thanks for your help,

Iñigo