Overlay multiple GIFs into one GIF file

is it possible (if yes, how) to overlay 2 (or more) layers of animated GIFs on a background image (PNG). The GIF files have portions of the image where it has transparent, so lower layers can be seen (such as the background). All the GIFs and the PNG background are of the same size. All GIFs have the same number of frames.

For example, I have a sun.gif file where it has 8 frames, and a human.gif has also 8 frames. Both GIFs are animating. And a grass.png, a static image, how can I overlay human.gif and sun.gif on grass.png, so you see a sun and a human animating, on a grass background.

Hey if you still have this issue you could check out how I managed to overlay gifs in my project canvas-gif. Currently all of the FPS values are synced but I'll be fixing that within the next few days. Hopefully this is at least of some use to you, and if you have any questions just give me a shout!

I hope this information helped. Please feel free to re-open with more details if further assistance is required.