more than one tooltips on grid

how can I insert more than one tooltip at same row. first tooltip when i hover mouse on first cell and the other on the second cell.
The example code only execute the last tooltip (on cell 1)

obj.getColumnTemplate(0).setAttribute("title", function(){return this.getItemProperty("tooltip")});
obj.defineDataProperty("tooltip", function(i, j){return "caller: " + myData[i][8] + " (a.n: "+myData[i][9]+")\naddress: " + myData[i][10] + "\nphone: " + myData[i][11]});
obj.getColumnTemplate(1).setAttribute("title", function(){return this.getItemProperty("tooltip")});
obj.defineDataProperty("tooltip", function(i, j){return "category: " + myData[i][12] +"\nmemo: " + myData[i][13]});