How to select to select several parts in the same track and low the volume of all those selected parts at once ?

Hi guys !

With Adobe Audition CC 2017 how can I select to select several parts in the same track

and low the volume of all those selected parts at once ?

For example :

I do VoiceOver and I just want to low all my breathings at once but not silence them completely, because it creates a vacuum.

And I don't want to use a plugin as DeBreathe (I have it) than can alterate the recording.

So now I low them one by one manually.

I would like to select several breathings at the same time and low all their volume at once.

The best thing would be to have Adobe Auditions selecting them automatically like  it is with :

Select "Effects > Diagnostics > Delete Silence (process)"  "Scan"  "Delete All" .

But instead of "delete" them, we could just low their db volume at once.

That would be nice.

Anyway, in the meanwhile, here is my question again :

How can I select select several parts in the same track

and low the volume of all those selected parts at once ?

Thanks a lot for your help.

(I hope I'm clear as english is not my first language)

Yves