That's a very good point @Julia Hennessey16. Currently we don't have this feature. I've added feature request tag to this question so our team can better track it.
Meanwhile, to better understand your use-case, what do you think should happen to the members that are part of the group? Should they see it under their groups list? Should they have access to it?
Also, by archiving, do you believe it should become readonly, or unavailable to regular users? If you think readonly is the way to go, do you believe the content inside of it should become readonly as well? For instance, should someone be able to answer a question inside an archived group?
Please feel free to add your valuable input as a comment to this answer.