Let's say you're in a store. The Verkäuferin asks "May I help you?" But you're there with friends who are already being helped. In English, you'd say "No thanks, I'm with them." What is the appropriate German for this circumstance? "Nein danke, ich gehöre dazu" ? "Nein danke, ich bin mit ihnen" ? "Nein danke, wir sind zusammen" ?