SAP PI Quota/self protection

Hi all,

lets assume I have two Interfaces connected to one SAP PI.

Interface 1 is sending IDOCs, Interface 2 is sending SOAP messages.

How can I make sure, that if Interface 1 sends 5 mio IDOCs in one shot that there a still enough resources available in PI to handle the messages from Interface 2?

From my experience PI is not doing any load balancing.