@GlennIngram We are able to confirm this workflow to have members of the same Organization edit the same style:
- create a group or use an existing group, add all the members that you want to access the style
- create a new style or edit an existing style. In My Content -> Layers -> Tile Layers, select the style you want shared.
- Click the Share button, on the Share modal, select Edit Group Sharing button, and share the item with your group
- In order for other members of the group to see this item, the can refer to it by its ItemID, or each member can go to Content -> My Groups, then select the group, and the Tile Layer should appear.
- You can load the tile layer in the Map Viewer Classic, and then the style editor icon will appear in the legend
--jf