Why should there be a rule about it? I mean, sure it is probably going to be a bit harder to write than sticking to one perspective, which means there is more chance to screw it up, but that does not mean you absolutely can not do it.
The most important question I would ask is why. Why do you feel this particular character should get a different perspective than the rest? If it is justified, go for it. If you just want to do it because you could, then you should probably think it over again. A justification would probably be, if the story is largely from this characters point of view, but you want to show parts of the story where the character isn't involved. So basically a first person story with cut-scenes. Whatever your reasoning, you should be consistent, so if this character appears, the whole thing should be first person. If he isn't there, go back to third. Otherwise it is going to be way way confusing, I believe.
