How to Play music with intro part,and loop at the time stamp?

We got an .wav file with looping timestamp( embedded by sound forge pro.)
Now we want to

  1. The first time we like to play from the beginning(with intro part)
  2. when BGM play to the end, we want to loop at the timestamp(skip intro part)

Out audio staff said simply checked the loop option in uasset, UE will automatically recognize the timestamp,
and do it all(1.2. above),
(as unity plug-in “introloop” do)
But We failed.

We’ve tried several way- to manually play inside BP(as image attached below),
-Use soundcue concat node to combine two audio
-Play loop part OnAudioFinished event on Intro part

But all caused a delay interval between intro part and loop part.

Is there any other better solution?