I am creating an index of teachers' names. Some of them are nuns. I do not have last names for these ladies just Sister Mary ___. Other teachers are listed with their last name in the first column and given name in the second column. They are alphabetized by last name. Do I list the nuns all together in the "S" list? As Sister Mary Pacifica or Sister Mary Paul? Or do I try to put them in columns too? But how? Thank you.

I would put all the nuns as last name in the "S" list, so when you sort them all by last name, all the nuns will be listed together:

Baldwin Mary
Darwin Susan
Sister Claire
Sister Dominicka
Sister Rosalind
Unger Susan
Zylo Christine