Yes I know that, I can add milion servers in whmcs but only one of them (one that is starred) is active and WHMCS creates all new cpanel accounts on starred server. But I need all of my servers to be active and have their own plans.
as I said above, I'm selling hosting from different countries, and each country has its own server (e.g. one in USA and another one in UK) now if USA server be our starred server and a customer buy a UK plan, WHMCS will create his account on USA server not on UK. I don't want this, I want WHMCS to create each plan on separate server with same control panel.
You'll need to create server groups, then add the appropriate server to that group. You can then select which group accounts are provisioned on under Setup > Products/Services > Edit > Module Settings tab.
█ The Complete Client Management, Billing & Support System