Substitute FILTER function in Excel 2007

[Stez84]

I have a table like the one attached. I need to get distinct values in column S (client name) but only of the records having a specific column A (supply code) value (OTT23 for example).
Is this feasible without using FILTER function?

Any help is much appreciated.

 

[Stez84]

=IFERROR(INDEX(dbOrdini[CLIENTE]; MATCH(0; COUNTIF($AB$2:AB2; dbOrdini[CLIENTE]&"") + IF(dbOrdini[CLIENTE]="";1;0); 0)); "")

I succeded to get the distinct values in the CLIENTE column. Now I should filter this result, showing just the client's with the right supplyCode

Really nobody can't help me?

 

[Stez84]

A better idea of my goal.

 

[Stez84]

Found the solution by my self, it takes 3 days but I'm happy now
link to solution: Extract unique values based on criteria with array formula