\EcommercePaymentSupportedMethodsProvider

if you want to implement rules around selecting specific payment gateways for specific orders then you need to extend this class and add the following to mysite/_config/config.yml: <code yml> Injector: EcommercePaymentSupportedMethodsProvider: class: MyCustom_EcommercePaymentSupportedMethodsProvider </code>

in PHP you will have something like this:
<code php>
class MyCustom_EcommercePaymentSupportedMethodsProvider extends EcommercePaymentSupportedMethodsProvider {
//....
}
</code>