This note studies the use of generalized sampled-data hold functions (GSHF) in the problem of simultaneous controller design for linear time-invariant plants. This problem can be stated as follows. Given plants P1, P2,..., P(N), find a controller C which achieves not only simultaneous stability, but also simultaneous optimal performance in the N given systems. By this, we mean that C must optimize an overall cost function reflecting the closed-loop performance of each plant when it is regulated by C. Applying GSHF to the simultaneous design problem, we give solutions in three aspects: simultaneous stabilization, simultaneous optimal quadratic performance, and simultaneous pole assignment in combination with simultaneous intersampling performance.