using DNS Hinfo to forward emails per email account

[Roy]

I am going to move my email accounts on my mail server to another server in
different domain in phases.
That is, userA at domain1.com is going to be removed from this server and moved
to a server in domainB.com.
I want the DNS forward any messages that is addressed to userA at domain1.com
to a host(mail server) in domainB.com.

I have seen AT&T doing this by using the HINFO record long time ago and I
need any help about how to use either HINFO record to do this task, or any
other method that you personally have experienced with.

Regards,

Roy