DNS enable only for spacific domain

[Mudasar]

Hi,

We have disable reject_non_fdqn_hostname, reject_non_fdqnsender and DNS checks in MTA,(decided by management because some valid mails are marked as SPAM or rejected we already give idea to add in white list but no luck ) after that SPAMs are very high. we have already enable RBL but still coming.

I observed that most of the spams are coming by using our domain, can i do any thing that dns(reject_unknow_clients) checking should be enable only for my domain.
Or any other idea .......