(a) Any party to a claim under this chapter, a group insurance company, or other health care provider who covers the costs of medical treatment for a person who subsequently files a claim under this chapter may give notice in writing to the board at any time during the pendency of the claim that such provider is or should be a party at interest as a result of payments made in the employee's behalf for medical treatment.

(b) In cases where a group insurance company or other health care provider covers the costs of medical treatment for a person who subsequently files a claim and is entitled to benefits under this chapter, the board shall be authorized to order the employer or workers' compensation insurance carrier to repay the group insurance company or other health care provider the funds it has expended for the claimant's medical treatment, provided that such employer or its workers' compensation insurance carrier is liable under this chapter for such medical treatment and provided, further, that such other provider has become or should be a party at interest pursuant to the provisions of subsection (a) of this Code section. The employer or its workers' compensation insurance carrier deemed liable for such medical treatment shall not be obligated to pay such sums directly to the employee unless, and only to the extent that, it is proven that the employee has paid for such medical treatment himself.