We consider the class of control systems that consist of a linear time-invariant forward path and a memoryless (possibly time-varying) nonlinear feedback. In this work we extend the small gain theorem in L(infinity) for these systems, in two ways. On the one hand, we generalize the approach to nonlinearities with bounds of arbitrary shape. On the other hand, we add structure to the analysis, dividing the vectors involved in the problem (outputs, nonlinearities, disturbances) into smaller dimension subvectors. This leads to less conservative conditions in the cases in which some structure of the nonlinearity is known. One important application is to the closed-loop robust stability analysis of a nonlinear plant controlled by a feedback linearizing and stabilizing controller. This is the case of an uncertain nonlinear model to be controlled, affected by measurement noise and external disturbances.