Nikon Z8 User Manual page 713

"Save Individually"
1
Assign [Recall focus position] to multiple controls.
2
Select another control in the custom control list and, when
prompted to choose a role, highlight [Save focus position]
and press 2.
Save options will be displayed.
3
Highlight [Save individually] and press J.
4
Focus on the desired subject in the shooting display and
press and hold the control to which [Save focus position] is
assigned.
A F icon will flash in the shooting display.
639
f2: Custom Controls (Shooting)