Please how is it possible?

My tooltip :
Code:
tips: {
							trackMouse: true,
							width: 74,
							height: 28,
							renderer: function(storeItem, item) {
							this.setTitle(storeItem.get('Week') + ': ' + storeItem.get(EACH COLUMN OF MY GROUPED COLUMN CHART));
							}
						}
Please help