I am not associated with Orchid Systems but do use their products and highly recommend them, therefore I would recommend looking at Orchid EFT Processing for Payroll (US and Canada) for the processing of payments via ACH https://www.orchid.systems/products/eft-processing-sage-300 fully integrated with the Payroll modules.  They have Youtube videos and more information on the site.  It also includes helpful features like splitting payments across multiple bank accounts for an employee, the generation of emailing of pay stubs, etc.  If you don't use the US or Canada payroll modules and just want to process payments via ACH from A/P then they have an A/P and A/R module for that too.  Hope that helps.