Each Customer can be added to multiple Plans manually. 

The customers can be assigned to a plan either via CRM or via Digigold. 

To assign a Plan to a customer via CRM:

Go to CRM

Search for the Customer > Go to Digigold Option on The right 

Assign a Plan to the Customer and add other values.

To assign a Plan to a Customer via Digigold:

Go to Digigold 

Under Customers > Select the Customer > Assign a Plan

Add other details and Save.