how to make a MovieTexture loop within a certain time slot?

Recently I prepared a MovieTexture and an AudioClip (my main menu theme) for my main menu scene. When the main menu scene is loaded, I make this soundtrack and the background video as a MovieTexture start playing immediately. The first 8 seconds of this MovieTexture (which displays a logo and a transition into the main menu) should be played only once, and it should loop between 8.0~15.5s when the time position of the main menu theme is at its verse, then loop between 15.5~23s when the main menu theme reaches chorus. I thought I should be able to do this by checking its current time position and compare it to the value of a scripted timer.

But as I look up in documentations (docs.unity3d.com), there are no functions or variables in MovieTexture showing how to modify current time position of a MovieTexture.

Is there a way to make it work? Or should I turn to plugins?