Methods and apparatus provide for: receiving tokens from a plurality of resources, where the tokens are exchange media for permitting a plurality of requesters to access an associated one of the resources for a period of time; allocating the tokens to respective requester groups into which the plurality of requesters have been assigned; receiving requests for one or more of the tokens from one or more of the requesters and granting, from the allocated tokens, one or more of the tokens to the requesters based on token granting criteria; and re-distributing unused tokens from one or more requester groups to one or more other requester groups based on priorities assigned to the requester groups; and dynamically altering the priorities assigned to the requester groups when a number of unused tokens of one or more of the requester groups has fallen below a threshold.