You can remove members from groups whenever you want to. These users that you remove are then no longer affected by the restrictions that still apply to the group.
Click your profile icon at the top right of the screen and then click Admin centre.
Click Groups in the left-hand navigation area and then right-click the group that has the member(s) you want to remove.
The Members section lists all of the members of this group. To remove members from the group, simply click the bin icon next to their email address.