Purging or cleaning a backup

I use WD Smartware Pro to continuously backup my hard drive.
Is there any simple way to purge or clean my backup? For example it would be great to be able to automatically purge backups of files I have deleted from my hard drive more than X months ago, but there is no such functionality in WD Smartware.

Any sugestions welcomed. Thanks

A synchronization software may be more in tune with your personal needs.