Passing ship sounds

The sound of ships patrolling and taking off and landing gets repetitive fast. I found I could mute it with one of the effects sliders but that also leads to silent guns, beasts, etc. Assuming the sound channels are not hard coded. can the patrolling ships be shifted to a separate channel with an independent slider/ mute. If the game designs any good the should channels should just be a set of sound file lists. But then this is an old old game by most standards.
I hope I'm not being a pest asking as I'm so new but we are meant to be alpha testing this design. I'm a very old crash test dummy. I did minecraft and pre-date the creeper there.