Repeat the setup for the Activities (on your home page under "Customize"). When it asks you if everything is set the way you want, tell it, "Yes but I want more control." It will then walk you through setup again, and then give you the opportunity to define sequences of commands to run at Activity start and Activity end.

Decide upon one Surround mode to be your base mode (the one you use most frequently). For all activities that use other surround modes, set up a startup series of commands to switch from the base mode to the desired mode. Set up an Activity end series of commands to return the Surround mode to the base mode.