How to achieve a Flexdashboard layout that has shifting orientations (and includes value boxes)?

Question

I am trying to achieve the following layout in flexdashboard: This includes a sidebar, five value boxes, a place for a map, and a right panel for text. My current attempt looks as follows: This was constructed using the following flexdashboard layout:

---
title: "Example"
runtime: shiny
output:
  flexdashboard::flex_dashboard:
    orientation: rows
    vertical_layout: fill
---

Column {.sidebar data-width=350}
-----------------------------------------------------------------------


Row
-----------------------------------------------------------------------

### Phase 1


### Phase 2 


### Phase 3 


### Phase 4 


### Phase 5 


Row
-----------------------------------------------------------------------
### Map

Row {orientation: columns}
-----------------------------------------------------------------------
### Commentary {.colored data-width=200}

How can I get the "Commentary" box to span the length of the entire right side of the page (as shown in the initial diagram)?