lucy24 - 10:54 pm on Feb 29, 2012 (gmt 0)
Do you mean visits originating at the central site, as opposed to "cold" visits going directly to the individual dentist's site? Or both? They're different things, trackable in different ways.
Are the other dentists' sites on pages within the originating domain, or do they have domains of their own? Again, different ways of tracking.