Hi, new member here. Does anyone know how to do this? I did do a search, but with no luck. Thanks in advance.

Welcome jricc,

Unfortunately multitrack doesn't have automation to automatically move the master gain during a mixdown. There are some workarounds to fade a song though. If the regions are long enough you could fade all the individual regions at the end of the song, by long-touching them and select 'Edit' from the Hotbox that pops up. The inner circle handles on the right of each region will control the fade out point.

Another way is to do a mixdown, then load that mixdown into a new song ('Region Copy' from the Shared tab, open a new song, then Hotbox 'Paste'). Then fade that single region and mixdown again.

Thanks! Will try both methods and report back.