Influenced by mouse/pen-based user interfaces, most touch-based object tagging techniques rely mostly on a single interaction point. Once objects are tagged, typically only individual object inclusions/exclusions are possible. Yet, for tagging larger groups with complex spatial layouts, more refinement may be necessary to achieve the desired result. We apply visual tag markers to objects to visualize their group association. Through a new multi-touch pin gesture that "pins" one or more objects "down" while tagging, our new interface is capable of efficiently grouping objects, as identified in our user studies.