Alternating two tones

I want to play two tones, t1 and t2, alternating with each other until some event. In order to start t2 when t1 is finished, I create a class, MyFoundationMBS, with superclass AVFoundationMBS, with an event handler “audioPlayerDidFinishPlaying”, in which I insert a call to play t2.

So far everything works as expected: t1 plays, followed immediately by t2. -The problem arises when I want to repeat the process employed for t1 for t2. MyFoundationMBS allows for only one Event Handler, - so how do I obtain an “audioPlayerDidFinishPlaying” event for t2?

If desired I shall be pleased to forward my code for the above.

Any help will be greatly appreciated.