Efficient nonlinear four-wave-mixing (FWM) interactions can be realized by either phase-matching or quasi-phase-matching (QPM) the optical waves involved. Conventionally, this is only achieved for a limited set of FWM processes. In this paper, we develop a method to simultaneously realize QPM of two arbitrary FWM processes. This double QPM method combines two QPM techniques, namely QPM by phase-mismatch switching for one process, and QPM by dispersion compensation for the other. To our knowledge, this scheme is the first one that can realize efficient interactions for two arbitrary FWM processes in essentially any type of waveguide medium that is characterized by a single zero-dispersion point in the wavelength domain of interest. We apply the proposed scheme to design two devices that can be operated at larger pump-signal frequency differences than previously possible, namely a wavelength converter switch and a one-to-two Raman wavelength converter. Hence, the double-QPM method allows optical waves to interact through a larger number of nonlinear optical processes, and enables novel FWM-based applications.