Deny by Thread Id

Is there a way that I can deny a transaction line by thread id?  I have 4 line items of transactions, and 2 out of 4 needs to be denied - so that when I select the "Approve" button the 2 lines where not checked/selected will be denied and the 2 other lines selected will be approved.  So basically I'm traversing through all the rows in the scroll area and where select flag = N will be denied; else if select flag = Y will be approved (as delivered this is already occurring when approve button is selected).  Any code example that can be provided will be greatly appreciated.