I don’t think that would work much better to be honest, because the groups would still hold resentment against eachother for a long time after. I fear it’d end up like what often has happened in post-colonial states with borders arbitrarily drawn by outside powers, where power struggles follow ethnic lines and frequent civil wars involve genocide. If an outside power even could impose that (and one should consider that Israel is almost definitely nuclear armed), then that power could also set up two or more states and enforce a buffer between them, or with power sufficiently balanced between the two sides as to deter full scale war.