What is the Sharee‘ah ruling on the Ahbaash sect?
Is it permissible to pray behind them?
Is it permissible to marry Sunni women to them?
Is it permissible to employ them in companies and institutions?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

There is no doubt that it is impermissible to pray behind a follower of anyone who has the creed that the followers of this sect do, or to let a follower of it marry a Sunni woman.

In terms of employing them, first priority should be given to employing Sunnis, nevertheless if it is necessary to employ a follower of this sect, the employer must make sure that the employee does not call others to follow his creed.   

Allaah Knows best.