What is the difference between grouping and stereotyping?

Stereotyping is a type of grouping that assumes that all members of the group have the defining characteristics. Stereotyping is related to prejudice.

http://www.members.cox.net/dagershaw/lol/Prejudice.html
http://www.members.cox.net/dagershaw/lol/PrejudiceChanges.html
http://www.members.cox.net/dagershaw/lol/PrejudiceUsThem.html

I hope this helps. Thanks for asking.