Add new AD group to sharepoint where ever another AD Group is exists

Hi All,

I have requirement to add AD Group called "Domain2\Facilities" to sharepoint where ever "Domain1\Facility" is exists in sharepoint(site, web, list, item ...) with the same permissions of "Domain1\Facility" using STSADM or sharepoint API's.   

As we dont want to iterate through all webapplication, sites, subsites, List and items because client is having more than 2000 site collections(huge data).  is there any better optimized way or predefined sharepoint way to achive this(like what we have for migrate user stsadm command)?

Note: I can not use Powershell script as it is sharepoint 2007

Thanks in advance.

Regards

Krishna