Xen CPU Core Sharing

Hi,
I want to start providing Xen VPS.
RAM and Disk will NOT be oversold. Obviously it will be a premium managed service so I need to ensure customers are happy!
However, I see most dedicated servers that I want to fit in price range, are Xeon Quad Core, for example, Intel Xeon E3-1245v2, and this means I could only fit 4 VPS per host node if I dedicate them a full core. Obviously this is not profitable unless you own your own full rack or own datacenter, which is definitely going to be the case down the road but not possible at this point.
I want to check, is there any way I can create three 4-Core VPS on a single Quad Core server, with Xen? Other resources like RAM and Disk Space will NOT be oversold.
Thanks for your input,
Shovenose