Hello Dhirendra,
You created the MX record on your external DNS?
You should create the MX record with the same weight as the other record you have, but with a different external IP. For example:
MX preference = 10, mail exchanger = mail.company.com.br IP = IP server X
MX preference = 10, mail exchanger = mail.company.com.br IP = IP server Y
If you have any doubts, let me know.