Read Sequence Names of Another Sequence

I am using a Sequence Call step inside my sequence file.

Under the Sequence Call step "Module" information I am setting the call to be "Specify By Expression."

For the "File Pathname" I am setting it to a pathname stored under a File Globals (Example: FileGlobal.FilePathname = Test Sequence (Example).seq.

When I set the Sequence Call step by Expression, the "Sequence" field is not a pull down since it does not know what the sequence "File Pathname" is until the test hits the Sequence Call step during execution.

I'd like to be able to read out all the sequence names for the called Sequence beforehand and store them as a File Globals variable so that I can use a variable in the "Sequence" field instead of a hard coded text sequence name to select which sequence to run.

Please see attached file.

Is there a way to get a Sequence to read out another Sequence's sequence names?

Thanks so much!