A few ideas...
Do a study of Esther and follow it up with a spa day. Give each other facials, polish nails, fix hair, etc. There are some ideas in this free download: http://www.brightideaspress.com/wp-cont ... %20FSG.pdf
Raising Maidens of Virtue would be good for a group of older teen girls. (some lessons are better for the 16-18 group) http://www.amazon.com/Raising-Maidens-V ... 0974339016
There are thought and discussion questions for each chapter, and activity ideas. It ends with a tea. Would be nice for mothers and daughters to do together, or at least invite the mother's for the tea.
My 14yo is reading A Young Woman After God's Own Heart by Elizabeth George and is really enjoying it.
You can look inside here: http://www.amazon.com/Young-Woman-After ... 0736907890
It looks like it would make a good group study.