Addressing widgets embedded in matrix objects

Hi again! I'm trying to rebuild my 'launchpad' style controller by using embedded matrix objects, representing tracks and clip slots in Ableton, but I'm not sure how to address or control values on the grandchild object (representing the clip slots). Do you have any insight?

Here's the structure:

panel container
----matrix (a) of matrix objects (representing tracks)
----matrix (b) of buttons (representing clip slots)

If I adjust the props for matrix a, it only affects the matrix b properties, not the buttons embedded inside of matrix b. How can I set the color, on and label properties of the clip slots without sending individual OSC messages for each button?

Here's a video of what I'm asking as well:

You could override the child matrix' props property but honestly I don't think it's a good idea to build a matrix of matrix widgets, it's going to be very hard to debug, I highly doubt you'll save time doing this.