cluster question

[Luciano Musacchio]

Hi,
I need to build a cluster for a physics research lab (gentoo nodes and bsd 
servers), There are many things to do here, but there's one I can't solve. I 
need to assure certain cluster power per group of user (research teams), each 
group own a portion of the cluster and they want at least that computer power 
when they need to use it. This makes it difficult to unify the cluster.

Here's my question: I've been searching and I've found this 
<http://www.linuxvirtualserver.org/>, now, there's some similar service on 
freebsd? or how you would solve this problem.

Thanks