In the 3.5 GHz Citizens Broadband Radio Service (CBRS), secondary users are managed by spectrum access systems (SASs) to protect incumbents from interference. Current practice requires each SAS to exchange detailed user information with other SASs, and to use a common algorithm to suspend transmissions so that an aggregate interference percentile is below a predefined threshold. We propose a simplified method that utilizes a tight bound on the aggregate interference distribution. Simulation results show that the proposed approach trades off a marginal reduction in spectral efficiency to greatly simplify incumbent protection procedure, allowing each SAS to independently manage its users.