Specifying Duration for a multi-part animation

In WPF using C#, I want to specify the Duration for each part of a multi-part animation of an object. If I use multiple figures, I cannot specify Duration for each figure because a Figure does not have a Duration.  Duration is set at the PathGeometry level. When I add multiple PathGeometries to the same object, only the latest one is kept.   

foreach (Clip thisClip in Clips)  
 {
 PathFigure ClipFigure = Clip.ClipFigure;
 MatrixAnimationUsingPath matrixAnimation = new MatrixAnimationUsingPath();

PathGeometry myPathGeometry = new PathGeometry();
myPathGeometry.Figures = new PathFigureCollection();
myPathGeometry.Figures.Add(ClipFigure);
matrixAnimation.PathGeometry = myPathGeometry;

matrixAnimation.Duration = TimeSpan.FromSeconds(thisClip.Duration);
matrixAnimation.BeginTime = TimeSpan.FromSeconds(thisClip.StartTime);

this.RegisterName("Clip" + Clip.Index.ToString(), canvasMatrixTransform);

Storyboard.SetTargetName(matrixAnimation, "Clip" + Clip.Index.ToString());
Storyboard.SetTargetProperty(matrixAnimation, new PropertyPath(MatrixTransform.MatrixProperty));
pathAnimationStoryboard.Children.Add(matrixAnimation);

}

How do I create a multi-part animation on one object while maintaining control of the duration for each part of the animation?