Business rule setup??

Hi All,

i have a requirement that to set up a business rule.

after approved the planning figures by board, we will sent to regional managers. region (in entity dimension) is a parent member and it's having base members.(branches)

The region user enters the values for base members. if the values (for base members of that region) entered by user exceeds the planning figure, then user will get an error message.

How can i set up this rule???

For setting the validation,  should we need flow dimension???

Thanks and Regards,

Naidu