Since the 5.5 release, you can use the root proxy feature combined with a custom renderer GeometryCollectionRootProxyRenderer
Make sure to set the Root Proxy Data as well with the “unbroken” mesh
The benefits of using this, is that the root proxy “Unbroken” mesh will use instantiated using ISM Also you will get benefits like LODs (If you don’t already use Nanite) from the mesh as well as Lumen support if you need it , until the geometry collection is broken
Hope this helps