Edward, there are a few VMSes that let you associate cameras together like that. It's not magic (the VMS can't just predict it). You need to manually configure these associations (i.e., in the setup for camera 43, mark the right side as linked to camera 40). Then on the live view, you could click on the right side of camera 43 and then it would automatically switch you to camera 40, without the operator knowing the name or ID of that camera.
We covered this in the VMS mapping shootout under the term 'suspect tracking.' Examples include Genetec's Visual Tracking and Milestone's Camera Navigator.
Those who are aware of others, please share.
It's sounds like you are asking for the system to automatically track a person across cameras and when they disappear from the FOV on one camera and pop up on another, that camera view is automatically called up.
This is not feasible in the current marketplace. For the most part the analytics technology isn't there yet, and in any semi-crowded area your "view" of the person (size, perspective, white balance/colors, resolution/detail) is going to change dramatically camera to camera.
Like any such application, you can contrive demo scenarios or selected cases where it can be made to appear workable, but it will not be reliable in a variety of everyday settings.
Have a look at Snap Surveillance. This software has algorithms that associate cameras close by automatically. Can even assess a large system and show what's not working and not associated using business intelligence...