How to Create cPanel Server Groups in WHMCS
WHMCS · Self-help guide
Server groups help WHMCS decide which cPanel server should receive new hosting accounts. In WHMCS admin, go to System Settings > Servers, then create or edit a server group. Add one or more cPanel servers to the group. Choose a fill type that suits your business, such as filling the least full server first or using a selected server order. Use clear names, such as UK Shared Hosting or Reseller Hosting Cluster, so staff know which group belongs to each product. After saving, open the product’s Module Settings and select the correct server group. Place a test order and confirm WHMCS creates the account on the expected server.