I see a few Rossiter entries but other close matches I see are
Ressiter, Rositer, Rosseter,
you can use wildcards to search for alternate spellings - for the above I selected Co. Wexford then put R*s*r in the surname search. It will then search for any surname that begins with R, includes an S and ends with R...
for Millar - Mayler, Meller, Miller etc
Shane