Various embodiments support two-way message service and voice communication. In at least some embodiments, temporary numbers from a pool of numbers are automatically assigned to outgoing messages and grouped with the intended recipient's phone number. Recipients can reply to the message by replying to the assigned number and the reply will be sent back to the originator of the message. In at least some embodiments, the pool of numbers includes different types of numbers such as, by way of example and not limitation, shared numbers and dedicated numbers. Further, at least some embodiments can utilize various policies in order to determine how to automatically assign temporary numbers. Such policies can be driven by business rules, regulatory concerns, carrier-based considerations, and the like.