This is a two part question:
1. Where would I go to change text in a group title to superscript?
2. Is it possible to use a "registered trademark" symbol in a group title (also superscript)
1. Yes. You can include <sup>MS</sup> in your title which will render as SuperScript.
2. No. This should be possible, but we block Emoticons from being used in Titles and ® has an emoticon equivalent and it is being stripped from the Title due to this. While most special characters are allowed in Titles, the few that have emoticon equivalents are being removed. I have filed a bug to see what we can do to prevent this.