Bree - - in addition to the artist groups which K-Mod Victoria pointed you to below, there is also already a well established group for authors. Rather than creating another new group for "Illustrators and Authors" the better course of action would be to add a discussion thread into these existing groups which already have a membership base.
We already have a few groups for people who create art. Rather than have another group for only specific subjects of art, please create a discussion thread or leave a comment in one of the already-existing groups. You can join them by following the links below: