issue in partner function:"responsible group"

Dear all,

please help me.

1. responsible group should determine after the Business partner enter to the transaction .

but in my case when i open any transaction it is already determined to transaction and after i enter the Business partner  again another  responsible group also determine. it should not be two responsible group for one business transaction type .

please suggest me to configuration.  so  after enter the business partner  only responsible group should determine.

attached some screenshot.

regards

Debasis