Call a vCO action from a Custom Decision

In order to be more flexible, can I call an action from the javascript within a Custom Decision. I am using the daily hypervisor 'Set Cusom Hostname" plugin. I need to check two external systems of record to do a collision check. I was thinking I would just hijack the HostNameExists decision and call my action that is already used elsewhere for a collision check. I am very interested in alternate approaches as well. Thank you