Hi Bogdan,
There is no such facility in JBoss Portal, nor will there ever be one as we have stopped working on JBoss Portal to focus our efforts on GateIn, our new portal offering. Note that monitoring via RHQ/JON is part of the things we look at for GateIn/JBoss Enteprise Portal Platform 5.
Is there any particular reason why you are still using JBoss Portal?