Not that I'm an expert in SMPS (I'm not), but personally I wouldn't do this. Firstly, you're assuming that the two series devices will ensure no more than 265V across one of the devices, and secondly you've got the input supply across the NO and NC terminals of the relay - something personally I'd be wary about (maybe I'm overworrying) but finally what if one of the contacts is a little slower in switching from parallel to series? Then, the top device gets the full supply across it.