That depends on your synchronization tool. The ActiveSync program from
Microsoft definitely cannot synchronize multiple contacts or journal
folders, which is what BCM uses. Third-party tools may be able to do so.
Chapura has updated its PocketMirror Professional utility to work with the
Business Contacts folder from BCM.

A forthcoming version of Intellisync will support BCM, but the version 5.3
or earlier does not.

I have also heard of people using Pocket Contact Synchronizer, a free tool
from Microsoft, to copy contacts automatically from the BCM Business
Contacts folder to your main Contacts folder. The main Contacts folder can
be synchronized with any PDA sync tool.

More BCM answers at http://www.slipstick.com/bcm/bcmfaq.aspx