" as for the ground wire does it just lay in the pipe, fastened on the collector end, or does it need to come in contact with both machines when they are running"
use a bare copper wire inside of all plastic pipe
solder all joints
have the wire(s) exit a hole in the side of the pipe and go to a ground rod(s) driven 6+ feet in the ground
does not need to connect to the machines as all the machines should be grounded properly thru the equipment grounding conductor back to the main panel