From the Advanced Configuration of each event (found from the bottom of the EVENTS page.
At the bottom of this page there is a "Merge events" section. Within this section, there will be events that have the same event code as the event you have selected. Use the check box(s) on the left to decide which events you wish to merge and then use the input fields (Gender, Age, Category & Name) to specify the details of the resulting (merged) event.
Click SUBMIT and go back to the Events grid to see the result.