Create a feature in the RadTileList control that allows the user to select multiple tiles, but only one (or maybe, any number - it could be a property that is set for this specific kind of selection) per group.
This was first discussed on this forum thread: https://www.telerik.com/forums/multiple-selection-single-selection-per-group and it's the reason behind this feature request.
The current workaround to overcome this "issue" is also available through that link.
This will allow to have different visual customization for the separate groups.
Make Tile.DisplayIndex property a dependency property so it can be can be set through data binding.
Please provide an event for when a Tile gets moved and/or when a Tile gets placed into a group or removed from a group. Something simple like OnTileMoved with event args pointing to the tile and new values (like updated group) would be peachy. :)