Yes and no is binary, so the question you're asking is probably the wrong one. There may be 2 questions. First answer is yes or no. then another question if the answer is yes where you take care of the maybe situation. That's just one possible solution though. You haven't really given enough information to help definitively.
Kimbo
When I did a Bank Merger, one of the projects was a payment system for mortgages.
If they sent in a check ...
It Met the payment amount (YES) ... went to the payment process.
It Did Not meet the payment amount, bad check, etc. (NO) ... went to the reject process.
Exception Processing - 'Maybe' - (can we somehow process this check ... like a pre-payment).
(Something Simple using your "Maybe")
By The Way ... I Used BPMN Editor 2.0 for the diagram ... It Was a FREEBEE.
http://sourceforge.net/projects/bpmn/
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