We use a mail server called mailhost.convergys.com which I have coded in the sendmail.mc and submit.mc file as below...

sendmail version: # rpm -qa |grep sendmai
sendmail-8.13.8-2.el5

[root@odccdds01 ~]# grep mailhost /etc/mail/*
/etc/mail/sendmail.mc:define(`MAIL_HUB', mailhost.convergys.com)dnl
/etc/mail/sendmail.mc:define(`SMART_HOST', smtp:mailhost.convergys.com)dnl
/etc/mail/submit.mc:FEATURE(`msp', `[mailhost.convergys.com]')dnl

An nslookup on mailhost shows:

[root@odccdds01 ~]# nslookup mailhost.convergys.com
Server: 155.90.250.207
Address: 155.90.250.207#53
mailhost.convergys.com canonical name = cvgmx1.convergys.com.
Name: cvgmx1.convergys.com
Address: 155.90.248.189

And mail is getting relayed to it for distribution as shiwn here:
May 19 04:17:24 odccdds01 sendmail[23063]: n4J8DNPd023063: to=mark.sylvia@convergys.com,michael.lense@convergys.com, delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=102546, relay=cvgmx1in.convergys.com. [155.90.248.189], dsn=2.0.0, stat=Sent (Ok: queued as B4129150EF7E)

The issue is, whenever mail is sent to: CVGcpu@perf.dcd.convergys.com, the relay is changed to: trivium2.dcd.convergys.com instead of mailhost.convergys.com and there is no connection....

May 19 08:17:24 odccdds01 sendmail[26368]: n4J3wmcF013985: to=<CVGcpu@perf.dcd.convergys.com>, ctladdr=<adm@odccdds01.convergys.com> (3/4), delay=08:18:36, xdelay=00:00:00, mailer=esmtp, pri=971290, relay=trivium2.dcd.convergys.com., dsn=4.0.0, stat=Deferred: Connection timed out with trivium2.dcd.convergys.com.

I don't see or understand where mailhost.convergys.com is being changed to trivium2.dcd.convergys.com ??? Any ideas as to what I may have setup wrong or where to check on this ?? I'm out of ideas...

You can run:
to find where this address gets rewritten. My guess it's happening in /etc/mail/virtusertable or etc/mail/aliases.
Or use:
to see details about that address.

# cd /etc/mail
# ll
total 244
-rw-r--r-- 1 root root 355 Nov 28 2006 access
-rw-r----- 1 root root 12288 Feb 4 14:29 access.db
-rw-r--r-- 1 root root 0 Nov 28 2006 domaintable
-rw-r----- 1 root root 12288 Feb 4 14:29 domaintable.db
-rw-r--r-- 1 root root 5521 Nov 28 2006 helpfile
-rw-r--r-- 1 root root 64 Nov 28 2006 local-host-names
-rw-r--r-- 1 root root 0 Nov 28 2006 mailertable
-rw-r----- 1 root root 12288 Feb 4 14:29 mailertable.db
-rw-r--r-- 1 root root 1048 Nov 28 2006 Makefile
-rw-r--r-- 1 root root 58202 Apr 20 13:51 sendmail.cf
-rw-r--r-- 1 root root 7304 May 19 11:37 sendmail.mc
-r--r--r-- 1 root root 41286 Apr 20 13:52 submit.cf
-rw-r--r-- 1 root root 988 May 19 11:37 submit.mc
-rw-r--r-- 1 root root 127 Nov 28 2006 trusted-users
-rw-r--r-- 1 root root 0 Nov 28 2006 virtusertable
-rw-r----- 1 root root 12288 Feb 4 14:29 virtusertable.db
# grep CVGcpu /etc/mail/*
# sendmail -bv CVGcpu@perf.dcd.convergys.com
CVGcpu@perf.dcd.convergys.com... deliverable: mailer esmtp, host perf.dcd.convergys.com., user CVGcpu@perf.dcd.convergys.com
#

The fact is that neither perf.dcd.convergys.com exists (at least I cannot resolve it from outside).
Since there is no user CVGcpu in aliases or virtusertable, the only thing I can think of is a .forward in the user's homedir.