You need to generate a found set of equipment records so that Replace Field Contents can update them to "Yes".
Let's assume you have a layout in your file named "Equipment" for displaying records from the equipment table.
From your "boxes" layout, run this script:
If [count(Equipement::EquipmentID) > 0]
Go To Related Record [Show Only Related Records; from table: "Equipment"; Using Layout: "Equipment (Equipment)"]
Replace Field Contents
Go To Layout [Original Layout]
This will mark all the contents of the current "box" record as deployed. THe If statment avoids a limitation of GTRR that keeps it from working if there are no matching records (If your Box is empty in this case.)
Thanks PhilmodJunk... you always provide excellent (and quick) solutions!