How can I use ColumnFlow with "heterogeneous" children?

[hagabaka]

It seems that ColumnFlow is like a Repeater, so you can only give it one delegate. However I would like to layout multiple elements in the same ColumnFlow. Is this possible?

In my project I have 5 GroupBox that are generated from a list model using Repeaters, and another "hard-coded" GroupBox. When I used GridLayout, I was able to use a structure like this:

GridLayout {
  Repeater {model: 5}
  GroupBox { }
}

The excess empty spaces in some GroupBoxes looked ugly, so I used your ColumnFlow. However, now I have to use

RowLayout {
  ColumnFlow {model: 5}
  GroupBox { }
}

If the last GroupBox could be also placed in the ColumnFlow, I would be able to use 3 columns and make use of screen space more efficiently.

My source code is here, if you are curious.