Seems like you want
Client_EventsGpluSHas the same features of the Save Events thing it seems you have but it has the option to Add saved lines of eventing to the end of other eventing without overwriting it.
The option is toggle-able via checkbox "Append", above the Load button on the bottom of the event screen.
When its on, the load feature will add the saved eventing to the end.
(I did not make this)