Two lightmaps in the same scene - Unity 5

Unity Engine
1

I have only a scene for my game - it’s easier to edit the whole game, and the transitions between screens are instantaneous. But now after I’ve switched to Unity 5, I can’t make 2 lightmaps for different levels in the same scene.
Did anyone find a simple workaround for this problem?
No matter how many lightmaps I bake, the same LightmapSnapshot keeps overriding all the light settings from the scene.

2

It should work with Baked GI only. If the scene contains Realtime GI also, it will not work.

3

I only want Baked GI. The problem is that Baked Selected button is gone in Unity 5. So I enable and disable different maps and only bake them. After I bake a map, I move the texture and the LightmapSnapshot in a different folder, and rebake a different map.
On each map I have a script that changes the current lightmap:

using UnityEngine;

[ExecuteInEditMode]
public class LightmapEnable : MonoBehaviour
{
    public Texture2D lightmapFar;
    public Texture2D lightmapNear;
    private LightmapData[] _lightmapDatas;
    public LightmapData[] lightmapDatas
    {
        get
        {
            if ((lightmapFar != null || lightmapNear != null) && _lightmapDatas == null)
            {
                _lightmapDatas = new[] { new LightmapData { lightmapFar = lightmapFar, lightmapNear = lightmapNear } };
            }
            return _lightmapDatas;
        }
    }
    void OnEnable()
    {
        LightmapSettings.lightmapsMode = LightmapsMode.NonDirectional;
        if (lightmapDatas != null)
            LightmapSettings.lightmaps = lightmapDatas;
    }
    void OnDisable()
    {
        if (LightmapSettings.lightmaps.Length > 0 && lightmapDatas != null && LightmapSettings.lightmaps[0].lightmapFar == lightmapDatas[0].lightmapFar)
            LightmapSettings.lightmaps = null;
    }
}

This worked in Unity 4.x but it does not work anymore in Unity 5.
I guess the UV info is lost once a new bake is done in the scene.
If you find a simple solution, let me know.