Positioning mixed size icons in a Visio group shape

In a previous post, I looked at one option for positioning icon sub-shapes within a group using a grid system.  This works nicely, but it’s based on equally sized grid rows and columns and therefore, equally sized icons too.  So in this post I'm going to have a go at trying to managed variable sized icons, while still retaining the ability of collapsing individual items so that the remaining visible icons concertina up next to each other.