Texture files (imageMaps) use a lot of memory. Back before I had 4 gig of RAM (which is still spartan) I'd get that error quite frequently even with one character (not 8) and some clothing and a few scene items. Come to find out some of the clothing items and scene items were chewing up a lot of memory, not to mention the figures' imageMaps themselves.

Depending on what your focus is on the image, you might find out what your imageMaps are and how big they are. If they are not a key part of the scene (i.e., they are not seen in closeup where detail is crucial) you might resize them in like Photoshop or the GIMP (which is free and does run on the Mac). Save out the resized images to something else - HeroTorso.jpg -> HeroTorsoSm.jpg, for instance - so you aren't over-writing your original image files, and in the Mat room, change the reference to the new file.

You can do this for bump maps too.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks