Physics question

Is it possible to set the physics properties of a body so that it will ignore specific other bodies? For example, Character will ignore a shelf and walk through it, but Character will not ignore the floor and will not fall through it. Item will not ignore the shelf and will fall and stop on it. Using isSensor does not work in this situation, as using isSensor allows Character to fall through the shelf but not to walk through it, since Character will no longer respond to the floor while isSensor is true. Thanks for your help!
[import]uid: 56297 topic_id: 23105 reply_id: 323105[/import]

http://developer.anscamobile.com/content/game-edition-collision-detection

categories and bit masks [import]uid: 21331 topic_id: 23105 reply_id: 92404[/import]

Thanks!
Collision categories, masking, and groups
is just what I needed. [import]uid: 56297 topic_id: 23105 reply_id: 92410[/import]