Internal Order status TECO and Close

Hello,

We have internal orders triggered through CRM. Whenever service order is closed in CRM, this changes the corresponding status of internal order to TECO.

A full settlement is carried out at the period end .Even after the status of internal order is TECO and full and final settlement is carried out, system is still allowing the FI postings for such orders. What settings needs to be carried out so that after full and final settlement and TECO status, FI postings should not be allowed.

The number of orders getting triggered through CRM are running in thousands in each month and user do not want to change the status of IO to "close" manually.

Any standard functionality is available for this? or I will have to go for developement? Please let me know in either case.

regards,

makrand