How to implement bindable property for children controls in custom control?

I'm implementing a custom progress bar,
where it contains multiple signs of progress with different colors:

This is how I think of it:

<controls:CustomMultiProgressBar OutlineColor="White" TailText="60%">
    <controls:CustomMultiProgressBar.Progresses>
        <controls:Progress ProgressColor="LightGreen" MaxPercentage=".4"/>
        <controls:Progress ProgressColor="DarkGreen" MaxPercentage="1" Image="star.png"/>
    </controls:CustomMultiProgressBar.Progresses>
</controls:CustomMultiProgressBar>

I found this lengthy article, but it must not be that complex.

all I need (if it was possible) a bindable property like IList<View> Children where its propertyChanged delegate handle rendering.