Check if form is being newly submitted, or being edited

When the owner of a form is viewing submitted data, there is an option for them to edit a submitted form. I have a group of questions that I would like be hidden from the surveytakers who originally fill out the form, but which would appear for anyone who is editing an already previously submitted form,

One way that I’ve tried to do this is by using validation criteria that tests if form metadata has been initialized (such as ${_submission_time} = null), but I keep getting errors saying that the variable doesn’t exist.

Can anyone think of a creative solution to this problem?
Thank you,

Hello Rick,
did you meanwhile find a solution?

We are also looking for an option to hide several columns/varaibles for non-owner users, but this is on the server, after submission. See topic.

I only found the setting option on the right top of the table view, which allows to filter the variables, but I am not sure, if every user, even with view right only, can change this. Furthermore this filtering is not transferred to the report.
Best regards