ExcelBanter - Formula Help for Duplicate Entries

I have a spreadsheet of 3000 contact names
I am trying to assign these in the most "fair" fashion to account
resps.

My thought was to create a colum called "account_rep"
I then put
account_rep_name1
account_rep_name2
account_rept_name3

In,
colum1,Row 1 account_rep_name1
colum1,row 2 account_rep_name2
colum2,row 3 account_rept_name3
colum1,row 4 account_rep_name1
colum1,row 5 account_rep_name2
colum2,row 6 account_rept_name3

the pattern continues respectively through the list to row 3000.

However, what has happened is that

there may be more than one account rep assigned to an account.

For example in the list I have.

account_rep_name1 Suzie Queen ABC Company
account_rep_name2 Suzie Queen ABC Company
account_rept_name3 Suzie Queen ABC Company

so, I want to assign unique rep to the account the first time his name
hits the account down the list.

What is the best way to do this?

Thanks,
Robert