You can certainly list the additional authors on the second title page. I'm not sure an additional heading "Authors of the set" would be helpful. Set of what? Without seeing the print or braille title page, I can't tell which titles are shown and which title is the title of the set and it that is clear on the title page. And I'm not sure this is clear to the reader anyway. I think the reader just sees the titles on the title page. I think you can just list the additional authors without specifying any further. You might have a heading "Additional authors" if you feel that would add clarity.