Identifying form events in perch_forms.received hook object.

I've been making good use of the new forms hook "perch_forms.received". I now have a situation where I want to process some forms but not others and the form name is not part of the PerchSystemEvent object that is provided by the event. The page array is of no use in this case as there are multiple forms on the page.

I can probably get round the issue with a hiden field in the forms but I was wondering if I was missing another way?.

Thanks

Kevin