MASQUERADE doing too much

[stfaprc]

I have misconfigured MASQUERADE somehow.
in sendmail.cf I have:
FEATURE(`MASQUERADE_AS',`def.abc')
MASQUERADE_DOMAIN(`def.abc')dnl
MASQUERADE_AS(`def.abc')dnl
FEATURE(masquerade_envelope)dnl

in submit.mc I have:
divert(0)dnl
include(`/usr/share/sendmail-cf/m4/cf.m4')
VERSIONID(`linux setup for Red Hat Linux')dnl
define(`confCF_VERSION', `Submit')dnl
define(`__OSTYPE__',`')dnl dirty hack to keep proto.m4 from complaining
define(`_USE_DECNET_SYNTAX_', `1')dnl support DECnet
define(`confTIME_ZONE', `USE_TZ')dnl
define(`confDONT_INIT_GROUPS', `True')dnl
define(`confPID_FILE', `/var/run/sm-client.pid')dnl
dnl define(`confDIRECT_SUBMISSION_MODIFIERS',`C')
FEATURE(`use_ct_file')dnl
dnl
dnl If you use IPv6 only, change [127.0.0.1] to [IPv6:::1]
FEATURE(`msp', `[127.0.0.1]')dnl
define(`confDOMAIN_NAME', `def.abc')dnl



this was done so that the FQDN would not show up when emails were being sent from the server itself.

problem is that we also do email hosting for domain HIJ.XYZ and all the email being sent from user@HIJ.XYZ is being changed to user@def.abc

How do i correct this?