Canon MACRO RING LITE MR-14EX II Mode D'emploi page 58

q: Wireless Multiple Flash Shooting with Manual Flash Output
If you shoot or fire the test flash with slave A and B positioned when C.Fn-
15-0 is set, slave A and B may fire. Turn off the slave A and B.
When <j> is set with C.Fn-15 set to 1, you can set any of A, B, or C
as the firing group for the slave units. Each group will fire according to the
set flash output.
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Set the flash output.
4
Press function button 3 <1> or
<8>.
Turn <9> to set the flash output,
then press <8>.
Repeat steps 3 and 4 to set the flash
output for all groups.
Take the picture.
5
Each group fires at the set flash
output.