Correct listing of names with suffixes

If I would like to create a list of which needs to be alphabetized and there are names with middle names/initials AND suffixes (Jr or Junior, Sr. or Senior, III etc), what is the correct way to display these names, when the last name need be listed first? Johnson Sr., George A. or Johnson, George A. Sr. or what? We cannot seem to agree and we are programming a system?