Can each Sand Soldier played by Weaponmaster attach its own equipment for a discounted cost?

Once a piece of equipment is attached to a unit, its own Equip activated ability becomes inactive, so you cannot simply re-equip it to a different unit for free — moving gear off a unit requires a separate effect. With Azir specifically, Weaponmaster (granted to your Sand Soldiers by his legend) effectively does this: it lets each Sand Soldier attach an equipment card when you play it, at a discounted cost. Weaponmaster only lets you choose one equipment card per Sand Soldier, but each Sand Soldier you play can use it separately, each attaching its own equipment for the discounted cost.