Fading Overlapping Symbols?

I've been using animate since it was Flash 8 and a Macromedia program, and from what I remember, back then if I wanted to fade out multiple symbols that were overlapping, I'd group them up and tween their alpha to zero.

Imagine I have a red circle on layer 1, and I convert it to a movie clip, and make a keyframe on frame 10 and set its alpha to zero, then make a classic tween.  That red circle will fade out on its own no problems.

Now, imagine I create a blue circle that partially overlaps the red on a layer above the 1st, convert it to a movie clip, make a keyframe on frame 10 and set its alpha to zero, then make a classic tween.

These objects will fade to nothing at the same exact time, but as they do it, the place where they overlap will be pronounced as it fades.

What I remember doing back in the day, or at least what I was sure would fix this was grouping the objects together and then tweening their alpha, which would eliminate the overlap and they'd fade as one object cleanly.

I tried grouping the objects, putting them in a single movie clip, and had no luck.  There's a new feature in Animate called Convert To Bitmap, doing that flattens the symbols into a bitmap and that works for the time being, but I'm concerned about the quality of the graphics when reduced from a vector.

I'm trying to see if anyone can tell me how to do this the right way, this is a technique that has existed well before Flash was called Animate since back in the Flash 8 days.  I was under the impression that grouping the symbols would fix this issue but in Animate the bitmap conversion is the only way I can accomplish the fade without overlaps showing.

Please someone who has been using flash forever must know what I'm talking about.