Background audio to continuously play in a loop presentarion

[Marcia]

Hi. I have a presentarion consisting the custom show and main presentation. The audio background of the custom show plays continuously but when the loop starts again on the first custom show slide, the music starts.
I would like the music to continue playing the song, not to re start at the beginning of the song.


I found some suggestions but applicable to version 2007 and below. I am using Microsoft 365.
Any help would be much appreciated. Thank you.