Limitations in an SQL query

Question

I have to make a report that shows the main customers of each seller (the top 10 customers who spent on each seller)

I am using the Oracle database to make this query.

Each seller has more than 40 customers, I need to limit 10 customers to all sellers.

The select I’m wearing:

 SELECT * FROM (   SELECT FILIAL, vendedor, CODV, cliente,SUM(valor), PERIODO fROM (SELECT ITPED.CODFIL FILIAL,
            ITPED.CODVENDR CODV,
            MAX(VEND.NOME) vendedor,
            cliente.nomcli cliente,
            SUM(ITPED.VLTOTITEM) VALOR,
            TO_CHAR(ITPED.DTPEDIDO, 'mm/yyyy') PERIODO
       FROM MOV_ITPED  ITPED,
            CAD_ITPROD ITPROD,
            VEN_VEND   VEND,
            cad_cliente cliente
      WHERE ITPROD.CODITPROD = ITPED.CODITPROD AND
            ITPED.CODVENDR = VEND.CODVENDR AND
            ITPED.CODFIL = VEND.CODFIL AND
            itped.codcli = cliente.codcli AND
            ITPED.DTPEDIDO BETWEEN '01/03/2019' AND '18/04/2019' AND
            ITPED.CODFIL = 3 AND ITPED.STATUS <> 9
      GROUP BY ITPED.CODFIL,
               ITPED.CODVENDR,
               ITPED.DTPEDIDO,
               cliente.nomcli

     UNION ALL

     SELECT ITSAIDA.CODFIL FILIAL,
            ITSAIDA.CODVENDR CODV,
            MAX(VEND.NOME) vendedor,
            cliente.nomcli cliente,
            SUM(ITSAIDA.VLTOTITEM) VALOR,
            TO_CHAR(ITSAIDA.DTNOTA, 'mm/yyyy') PERIODO
       FROM MOV_ITSAIDA ITSAIDA,
            CAD_ITPROD  ITPROD,
            VEN_VEND    VEND,
            cad_cliente cliente
      WHERE ITPROD.CODITPROD = ITSAIDA.CODITPROD AND
            ITSAIDA.CODVENDR = VEND.CODVENDR AND
            ITSAIDA.CODFIL = VEND.CODFIL AND
            ITSAIDA.codcli = cliente.codcli AND
            ITSAIDA.DTNOTA BETWEEN '01/03/2019' AND '18/04/2019' AND
            ITSAIDA.CODFIL = 3 AND ITSAIDA.STATUS <> 9
      GROUP BY ITSAIDA.CODFIL,
               ITSAIDA.CODVENDR,
               cliente.nomcli,
               ITSAIDA.DTNOTA)  GROUP BY FILIAL, vendedor, CODV, cliente, PERIODO ORDER BY 3 ASC, 5 DESC ) WHERE ROWNUM <= 10

I was wondering if it would be possible to make a Loop by passing the sellers' codes, because I was able to limit the amount of line the select returns.