@Rocky_Stone Hi! Hmm unfortunately just not yet. There is a feature in preview that will allow you to move multiple drawings on the timeline but this is under review, but this is mostly to fix stuff at the same time, not for motion interpolation.
Your other option is to use the “camera layer” we have a guide to learn about it here: [Guide] Understanding the Camera Layer
So basically the easiest way is you animate a large horizontal background moving, export that and then use that image sequence as the actual background for the character walk.
I mention image sequence because GIF’s have low quality as they are old web standards, so better export a sequence of PNG images if you want to retain maximum quality.
Now to be honest for what you need right now, it might be better if you make the walks in pencil2D and then use other software to move them. I can recommend Synfig as it has motion interpolation out of the box. think of it as more of a compositing software for animation or a motion graphics software.
So you’d import your BG, then you’d import your image sequence for each character and each thingy will be seen as an object and can be moved independently with relative ease.
If you need further help let us know, we don’t mind if you use other software 