World Partition handling of placed but moveable actors

how would one handle actors which are placed inside the editor but should be moveable by the player.
For example having a vehicles, with World Partition those would despawn even if it is the current possessed pawn, if one leaves the cell it was placed in!
Or having some moveable items, which are transported by the player through out the map?
As example if a vehicle is set to spatially loaded false, but the actors on the cargo are set to spatially loaded true, the items would unload if the player leaves the cell!

Setting those items to spatially loaded false does not work as well if they depend on physics. They would just fall down if the HLODs are unloaded at higher distances!

I just try to get my head around how to work with world partiation in those cases were there are some dynamic actors in the world, while still profiting from World Partition.

I tried looking at runtime changes to bIsPatiallyLoaded or DataLayers, which do not work as they seem to be cached on World Partition initializiation.
Even tried to spawn a WorldPartitionStreamingSource, even with higher priority, but everything is still unloaded! It seems that the Streaming Source just does not work at all in those situations.

Maybe some one can enlighten me how to handle those situations or if WOrld Partiation is just to limited to be used?

Best Regards