Multiple scattering from a cluster of nonlinear point attachments on a beam is formulated and analyzed. The nonlinear equation of motion is solved using a perturbation strategy. The analytical solution is implemented for two common mass–spring–damper systems and for either nonlinear stiffness or nonlinear damping of power-law dependence. The nonlinearity generates harmonic waves at frequencies that are multiples of the incident-wave frequency, and also shifts the linear response of the fundamental frequency. In addition to asymmetric reflection, which is also achievable using linear scatterers with damping, the cluster of nonlinear scatterers can produce asymmetric transmission, thus breaking reciprocity of the system. Analytical results for a single scatterer are presented and validated using Finite Element Method simulations with perfect agreement. A two-scatterer nonlinear cluster acts as a filter that is tunable by the incident amplitude and a three-scatterer cluster that acts as a non-reciprocal frequency converter are considered, demonstrating the potential of the proposed framework for the design of nonlinear scatterer clusters with more complicated scattering properties.