Mission planner moving home

I’m using mission planner base GCS
but, there is a problem here
I want to make the moving GCS follow when I use the RTL
function for the multicopter
Both GSC and multicopter are using GPS
Is there any plan for this?

You can reset your home position by sending the Mavlink msg to the multicopter
Refernce is as : MAV_CMD_DO_SET_HOME you can send this msg to multicopter when your GCS change positions.

The command brief as :

Sets the home position to either to the current position or a specified position. The home position is the default position that the system will return to and land on. The position is set automatically by the system during the takeoff (and may also be set using this command). Note: the current home position may be emitted in a HOME_POSITION message on request (using MAV_CMD_REQUEST_MESSAGE with param1=242).

How do I control this message???
Should I set up sending MAV_CMD_DO_SET_HOME to mavlink protocol??? how control the message

You have to write a code yourself you can use pyMAVlink to capture your GPS coordinates from GCS and send it to drone.