Intratech's "Smart3D DBX to NWC" software exports NWC from S3D with embeded "Selection Sets". In Navisworks, it works fine. However I couldn't find a way to retrieve "Selection Sets" from SVH2 with Forge API. Am I missing something ?
I'm sorry that the selection set is not supported currently since no other model formats support it. So, I would advise you to use Naivasworks API to extract the selection set out and store it somewhere, then host a Web API service to serve such data.
If you want to know how to map elements between viewer and Navisworks, please check my answers here: https://stackoverflow.com/a/56985615/7745569