MainCamera.cs

public class MainCamera : MonoBehaviour
{
    public Transform[] Players;

    public Vector3 Target;
    public Vector3 BaseOffset;
    public float Speed;
    public float YZoomFactor;
    public float ZZoomFactor;
	
    void Update ()
    {
        Vector3 max = new Vector3(Mathf.NegativeInfinity,0f, Mathf.NegativeInfinity);
        Vector3 min = new Vector3(Mathf.Infinity, 0f, Mathf.Infinity);

        for (int i = 0; i < Players.Length; i++)
        {
            if (!Players[i].gameObject.activeSelf) continue;
            if (Players[i].position.x < min.x) min.x = Players[i].position.x;
            if (Players[i].position.z < min.z) min.z = Players[i].position.z;
            if (Players[i].position.x > max.x) max.x = Players[i].position.x;
            if (Players[i].position.z > max.z) max.z = Players[i].position.z;
        }

        Target = min + ((max-min)/2f);
        Target.y = BaseOffset.y + ((Vector3.Distance(min, max)) * YZoomFactor);
        Target.z = (min.z + BaseOffset.z) - ((Vector3.Distance(min, max)) * ZZoomFactor);

        transform.position = Vector3.Lerp(transform.position, Target, Speed*Time.deltaTime);
        transform.LookAt(min+((max-min)/2f));
    }
}