Hi @japel
A good point,
I don’t have an answer off the top of my head, but my first idea is to look at the data in the $_POST array. Perhaps there is something in there that you can use to differentiate the forms?
The acf_form function contains an option to add extra HTML after the fields. You could use this to add in a hidden input containing an ID or something similar.
Good luck!
Cheers
E