There is a way but I would just kill them if there small enough of a group, take the mage first and then rogues damage is tankable and easy to dodge.

Use your cart physics to break their ward or let a gjall blast the place if you don't want to anger them I spose, but imo your still damaging their stuff and hurting them so the "pacifist" way of getting their stuff is just a technicality that lets you sleep at night lol