Play multiple animations with Animator.Play()

I'm building an animation preview tool, and the artist wants to see animations from all layers play at the same time.

For instance layer 1 is upper body, layer 2 is lower body. Layer 1's selected state is "Row_upper" and layer 2's selected state is "Row_lower".

 GetComponent<Animator>().Play("Row_upper", 0, Time.time);
 GetComponent<Animator>().Play("Row_lower", 1, Time.time);

But only the last called animation will be playing. I know animation masks and such are properly setup, it all works in the game. I just want to give the artist a good tool to preview their animations in engine.