Round Reset/Cleanup?

I've implemented rounds into my game (much like Counter Strike). After the round starts, all objects added to the game get added to a RoundCleanup group and deleted when the round ends. This worked fine until recently.

I have PhysX objects, as well as objectives in the maps now. These objects get moved and, for objectives, some of their states change. I'm wondering what the best way would be to restore the map back to how it was when the game started.

I'm thinking maybe destroy all objects in the game then reload the .mis file. I just don't know if that would put a lot of load on client PC's at the end of rounds.

Thanks for the insight,
Matt