Do each of the forms form tags, meaning they are separate forms or are they all included inside a single form. By default each acf_form() is a separate form and must be submitted separately unless you’ve set the ‘form’ argument to false. If you have not done this then the fields of one form will not be submitted with another form.
If you do have them all in one forms, then there isn’t any way to tell which fields go with a certain form except to check each field key. If each form is a separate field group then the “parent” of each top level field object will be the field group key. But there isn’t any way to trigger a different filter based on this information that I know of.
Not sure if any of this will help you or not.
