Hi Vishnu,
I think you can try some thing like the code below:
(@Select(Sales Geography\Country Group) IN @Prompt('Select Country Group or
enter * for all groups','a','Sales Geography\Country Group',multi,free) ) OR
('*' in @Prompt('Select Country Group or enter * for all groups','a','Sales
Geography\Country Group',multi,free))
Might be helpful solving your issue.
Regards,
Rishabh