Well we need to append to: parameter for each location. The url scheme will be as follows:
from your current location
comgooglemaps://?daddr=Lat,Lon+to:Lat,Lon+to:Lat,Lon+to:...if you have source location
comgooglemaps://?saddr=Lat,Lon&daddr=Lat,Lon+to:Lat,Lon+to:Lat,Lon+to:...