Sales Blanket Agreement stored prusedure

Dear Community

i need to create a stored procedure on Sales blanket agreement so all the linked marketing documents which are related to it can not exceed the blanket agreement total amount

Ex. i have blanket agreement with Client X with total amount of 100000

and i created sales quotation(or sales order) based on it with total amount of 60000

then i want to enter another sales quotation( or sales order) with 50000

i want System give me massage that i must have approval on the second SQ because it will exceed the total amount of the Blanket agreement.

your help is highly apreriated