Is it possible to lock certain rows in an editable table backed by an array

Summary

Transactions Query brings in headers and lines

Content

Hello,

I have an edit screen configured that is populated with a single transaction at a time.  The header is a filtered get call from a business object.  No problem there.  The Lines are filtered from another business object and populated in the lines array.  Here is the nuance.  I would like the rows that are loaded as part of the original transaction to be locked or not updatable.  There is a button that allows a user to add another line that can be entered and saved.  However, the original lines need to be locked.