Ranking Filter Not Recognizing Duplicates

[Kkelly36]

Hello, I am a bit new to Cognos and I am try to create a ranking filter for a list of email addresses where if there are duplicate email addresses, I want the business account to be prioritized over the consumer account. I labeled Business a 1 and Consumer as 2. Im then using that in a filter rank([email address] for [email address], [business priority]) but this is ranking all the email addresses as 1 and not recognizing duplicates. Is there something I'm missing? Thank you for your help!