Every insurer shall conduct its business in the State in, and the policies and contracts of insurance issued by it must be headed or entitled by, its proper or corporate name; provided, however, notwithstanding any other provision of law, an insurer may elect to use a trade name in the conduct of its business if the insurer also clearly discloses its proper or corporate name on its policies, contracts of insurance, and other documents filed with the Department of Insurance. Two or more authorized insurers may, with the approval of the director or his designee, issue a combination policy which shall contain provisions substantially as follows:

1. (1) That the insurers executing the policy are severally liable for the full amount of any loss or damage, according to the terms of the policy, or for specified percentages or amounts thereof aggregating the full amount of insurance under the policy; and
2. (2) That service of process or of any notice or proof of loss required by the policy upon any of the insurers executing the policy constitutes service upon all the insurers.