An exactly soluble model of the weak decay of a 0"^ particle to three strongly interacting 0"^ decay products is investigated numerically in order to explore the effects of final-state interactions (FSI) on the decay and the way in which the resonant-pair interaction information is distributed over the three-body final state. We find that moderately strong attractive pairwise FSI can produce very large enhancements or de-enhancements in the decay rate, but we find no effect of rescattering singularities. We find that large effects on the decay rate can be accompanied by pure phase-space single-particle spectra. The effects of interference between various terms in the amplitude make the extraction of pair-resonance parameters from singles spectra chancy, and there is no obvious trend in the deviation from the input resonance parameters. These interference effects also produce striking and possibly misleading patterns in the Dalitz plots.