SAP Web dispatcher

Hello Experts,

I want to gather information regarding the configuration of SAP web dispatcher. We have an SAP CRM system which is accessing via SAP Web dispatcher. CRM system have 2 diaglog instances and one central instance. Now we need to deactivate central instance from user access. I know, I can deactivate it through dispatcher admin gui. But this deactivation will go away once system is getting restarted. So, I need to configure the system as deactive permanently in web dispatcher. I came to know that some parameter setting will do this function. Please help me to configure.

Appreciating your directions in advance.

Siby