Parent iframe disabled after merging projects

We have several testers work on a website, and everyone records one part alone. We merged all projects into one using a file manager but new test cases are not working because of all the parent objects are switched to “No”.

So basically we need to reassign every parent iframe to each object but we have more than 1k obj to do and it looks exhausting.

Do you know any ways how to reassign the parent iframe for all objects inside the Test case or maybe do you know another way how to merge several projects into one without this issue. Thanks.