Andrea has an overview of Microsoft Dynamics GP 2013 R2 – Payables Management New Features!!
Microsoft Dynamics GP 2013 R2 – Payables Management New Features!! – Dynamics GP Support and Services Blog
Tips & Hidden FeaturesPayables & ReceivablesGP 2013
Archived post from 2014. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.