Methods and apparatus for shared access systems may be used to allow operation in three-tiered shared spectrum architecture. For example, a Shared Spectrum Manager (SSM) may organize spectrum segments. The SSM may communicate with access users of different priority and may use message exchanges to request spectrum, bid for spectrum, manage spectrum, or the like. The SSM may manage admission of access users (allocation of spectrum to users) and operation with a spectrum request that may be provided as a range between a minimum (guaranteed) and maximum quality of operation. The SSM may also manage the way an access user may use the assigned spectrum. Inter-SSM communication may be used in regions where multiple SSMs may exist (e.g. country borders). Accordingly, triggers for this inter-SSM communications and corresponding actions are also disclosed herein.