Eric Fomba - you can achieve in two ways
1. Create a group_max formula as Max value: group_max (revenue )
Then use the following clause in search bar: max value client in (client max value) if you are in 5.3.2 version and above
2. If you are below that version
create another flag to compare revenue with max revenue as
Max. flag: if (revenue = max value ) then 1 else 0
then use the following clause in search bar: client revenue max. flag = 1
Screenshot is attached for both.