@Andrea - Another approach. You can change the calculation level argument to PRE_AGG for the Rank function. Then you can use the calculated field in your other calculated fields without having the dimension in your field wells.
You can change the partition field in the rank according to your use case. For this example I’m showing the last alphabetical customer’s total sales by region.
c_last_alphabetical
ifelse(1=rank
(
[{Customer Name} DESC ]
,[Region]
,PRE_AGG
),'Yes','No')
c_last_customer_name
ifelse({c_last_alphabetical}='Yes',{Customer Name},NULL)
