Systems and methods of routing calls may include receiving a plurality of calls, and for each of the plurality of calls, determining a threshold time that may be a maximum service time for the call, estimating an expected service time for the call, comparing the threshold time with the expected service time for the call, and assigning the call into one of a plurality of queues based upon the comparing. The method of routing may further include prioritizing the plurality of queues based upon the expected service time for each call in each of the plurality of queues, directing each call in a first queue of the plurality of queues to a first group of agents, and providing a callback prompt to each call in a second queue of the plurality of queues, wherein a priority of the first queue is higher than a priority of the second queue.