As already said, if you are targeting the same domain for link wheel creation. You can have one account to make another wheel. I don't see any problems with that. But its not a big deal even if you create separate accounts for each link wheel. I mean no harm in that as well, just some hassle.
The best thing to do now with Link Wheels is to create a broken link in the wheel. The reason for this is it gives a more natural affect to the Link Wheel process and Google is catching on to the Link Wheels which are very affective. It does not matter if you have one account or a different account at all. The only thing that matter is the natural feel to the search engine bots.