@Wildberryjack That is correct - all of the 3D graphics code is written within Essential Housing Tools for these special effects, so the add on is required to add or to see any of them.
So, as long as someone has the latest Essential Housing Tools and is in your group, they will automatically begin receiving the data necessary to reconstruct your Effects on their end within a few seconds after they port in.
If you do have any issues, always confirm that you and they have the latest version. If you do, try ungrouping and regrouping. This forces the data transfer to repeat itself.