A system, apparatus, and method for routing work items to agents, wherein the work items can be of one of two or more different communication media types from one of two or more different communication channels. A queuing engine includes a list of routes and each route is associated with one or more properties. The list of routes can further include information related to one or more escalation rules for each route; the type of communication media available along the route for handling one or more of the work items; whether the route is active; the priority of the route; whether work items can be handled real-time; the service level for work items handled on the route; and the number of work items that can be assigned to the route. The queuing engine determines various properties required to handle each work item, such as the communication media type, agent language and skill level, and the category and recipient of the work item, and to assign each work item to one of the one or more agents based on one or more of the properties. When the queuing engine determines that a work item has been waiting a predetermined amount of time to be assigned to an agent, and the queuing engine can escalate the search for an agent to handle the work item based on the escalation rules. The queuing engine can also substitute values for variables in the routing and escalation rules, thereby reducing the number of rules that must be entered to achieve the same routing capability.