One of the unique feature of the Godox X1T is that it allows you to change the power output of all the flashes grouped on the same channel while maintaining the ratios.

STEP 1:
Hold the GROUP button on your #GodoxX1T until the flash power starts blinking.

STEP 2:
Use the dial to change the power output on all the flashes simultaneously.

STEP 3:
Press the CHANNEL / MODE / GROUP button to confirm selection.