Yes, this can be done pretty easily. First apply the Gantt Chart view and then drag the split bar to the right edge of the Predecessors column. Select the two tasks that need to start at the same time and then link them with the default Finish to Start dependency. In the Predecessors column for the SECOND of these two tasks, you should see the ID number of the other task. Add the letters SS to the ID number (for example, 9SS) and then press the Enter key. Hope this helps.