Once you escape that jacket, all you have to do is:
1) For a new deviation - along with boxes for which of your Folders you're submitting to, you can check the box for the Group (at submit time) or Groups that you'd like to submit to.
2) For existing deviations - there is a button along the right side, near the bottom of the page, labelled " + Add to a Group " so click that, and choose "Submit to Group Gallery" up top, "Type a Group Name" button, type in " The-Mental-Ward " and go from there. (After that you should see the Group, in future submitting efforts, listed in Recent Groups when you do this.)