You will need to read over the terms of your personal liability and physical damage coverages (comprehensive and collision) policy as well as and speak to your insurance company to find out for certain what, if any, of these coverages would extend to the vehicles you drive at work.

Generally insurance companies allow these coverages will extend to other vehicles, such as rental cars, but since you are driving various cars for your job your policy may have an exclusion about the coverage extending for business use.

If your personal coverage does not transfer to the "company" cars at your workplace, you may want to speak to the dealership about an auto insurance business policy that employees would be able to be part. A policy that would cover the vehicles for collision and comprehensive while you and other employees or potential buyers were driving them for demonstrations.