To Bulk Import the policies you have two options.
In GPMC, right click a GPO (not the link) and select BACKUP -- or right click the GPO container and BACKUP ALL
In the other domain IMPORT the GPO from the backup file
Also look in GPMC at the "Migration Tables" which handles information specific to the domain when moving GPOs.
Refer these links also
Backing up, Restoring, Migrating, and Copying GPOs: Group Policy
Import a Group Policy object using GPMC: Group Policy
Bulk Import of Group Policy Objects between Different Domains with PowerShell - Manny Murguia's Blog - Site Home - TechNet Blogs
Bulk exporting and importing WMI filters for Group Policy - Ask the Directory Services Team - Site Home - TechNet Blogs
I hope it helps you.