how can i change incoming mail server with smtp server

[resif]

i dont wanna use mail.sitename.com as my incoming mail server..
so how can i change it with my hostname server...

my hostname server is also my smtp server....

i want to use my hsotname server server.sitename.com as my incoming my server...

by this way my mx record will be server.sitename.com as my incoming and outgoing server....

is that posibble bcos i am using my site mails with gmail