Hi, @jjm_335 ,
(sorry, I probably misinterpret your desire…, anyway I leave the below selection tip in any case…)
Selection tip
select one box (the big ones are system related, the little ones are staff related) and then click Shift + down arrow (or up arrow) to extend the selection for further boxes of the same kind (system or staff):
Here an example, first for system boxes, and then for staves boxes selection:
