Dashboard Query Prompt Default Selection

Hey Guru's

• I have requirement in Xcelsius Dashboard that to use query prompt selectors. like i am using three prompt from the single query.
• First prompt is of country where all the countries are appearing to which my company exports, second is of customer, and third one is of product sold.
• My question is that if i select the particular country like "CHINA", so the next prompt which is of customer should only show the customers which resides in china but the problem is that it shows all the customer database as whole so from such a long list it is almost impossible to search particular china customer. Same is the issue with product like it should only show product which i sold to china and to particular customer.

Kindly Help me in this issue how this can be tackle and any alternate to overcome this issue.

Thanks and best regards,

Hassan Ali.