User defined return to launch (RTL)

I’m attempting to establish a user-defined return to launch (RTL), which appears on the map in different colors. In Plan/Flash view, we can currently see only one map, which is the mission planner. I’d like to present two maps in various colors. 1. Mission planner 2. RTL defined by the user Could you please tell me if I add user defined RTL, if I need to change the data structure simply for the UI? For only UI which files need to modify.

Thank you in Advance.