Colo. Rev. Stat. § 25-3-314
Any hospital which is owned by a county, or by a city and county, having a population in excess of two hundred fifty thousand persons and which is a teaching hospital duly accredited as such by the joint commission on accreditation of hospitals and by the council on medical education of the American medical association may employ physicians and surgeons licensed to practice medicine in the state of Colorado for the performance of professional services in such hospital or in any related outpatient facility which is owned by such county or city and county. Charges for the services so rendered by any such physician or surgeon, excluding professional trainees, may be collected through the medium of such hospital in the name of the physician or surgeon and, upon collection, may be placed in a medical practice fund to be established, maintained, and used by such hospital solely for the purpose of payment of compensation to the physicians and surgeons so employed and for the payment of consultation fees to other physicians and surgeons not so employed, or directly to physicians and surgeons who are directly engaged in medical research or medical education.
C.R.S. § 25-3-314