Yes, though you'll probably need to write a script. QF session files (.qfx) are XML files and can be navigated and modified the same way as any XML file (e.g., using XPath or a similar mechanism).

I strongly recommend backing up your QFX file by making a copy of it before you do any programmatic modification, however.

Also, some parts of the file are encoded (e.g., sample document images, connection profiles) and are harder to update programmatically (though it's still possible) and can have other consequences (e.g., fields not being updated).

Note: updating the QFX file manually is not officially supported and you do so at your own risk