Share email account between google apps and zoho mail on same domain problem

Share email account between google apps and zoho mail on same domain problem

Hi guys

I need some help on setting up my email with google apps mail and zoho mail.

I have 3 email on google apps and 3 email on zoho mail
Example :

Google apps email
a@mydomain.com
b@mydomain.com
c@mydomain.com

Zohomail
d@mydomain.com
e@mydomain.com
f@mydomain.com

I have done everything and its working except i cant email between each other within the same domain emails
a cant send to d
e cant send to b
f cant send to c

Anyone know how to resolve this issue or turnaround.