An alternate firefighters retirement and disability plan may be implemented by a firefighters relief association in lieu of the plan provided for in chapter 18-05. Before a relief association may implement the plan provided for in this chapter, a vote must be taken among the members of that relief association to determine whether the association will adopt the plan authorized by this chapter or retain the plan established in chapter 18-05. If the members of the association vote to adopt the plan authorized by this chapter, that plan does not become operative until the city government of the community in which the fire department is located has approved the plan.