From this post: No Sound Attenuation in Sequencer Audiotrack
You actually can add/attach an audio clip to a particular actor in Sequencer and it will respect spatialization. Before you drag the audio clip in, you need to select the actor. You’ll see that the audio clip gets added to an audio track which is under the selected actor. To make this functionality more evident in the future, we’ll add a drop target so there’s some sort of highlight when you drag the audio clip in.
Does that help?