There is a need to create a contact report containing list of contacts that have common email ids. This list should not contain any contact with unique email Id . I would appreciate detailed instructions.

The approach I took is to create a contact record type report grouped by email Id. This gives me the email id count but it does not allow me to add a filter ( > 1) on grouped by field to filter out unique records. I also tried creating a summary column and adding a function to get row level count.