Hangouts participants will now have the ability to remove other participants from a Hangout. This is only available to people from the same domain as the Hangout creator. For example, if a person creates a Hangout from Calendar, people in their same domain will be able to eject others from the call. Any participants from outside the domain will not have this ability.
Ejected external participants will not be able to re-join the call unless explicitly re-invited by a person within the domain. Ejected participants from within the domain can re-join with the invite link.
For more information: