The Org settings area

People are managed on the Organization tab → People now - one directory for everyone, with invitations, seats and pending join requests above it for admins. Old links to Org settings → Members land there automatically.

In Administration → Sub-organizations, each sub-organization has an Edit button (also on its right-click, long-press or Shift+F10 menu). It opens the same choices as creating one: its name, industry, colour, timezone and team email; Bring people along, to add people from this workspace - pick them, or Add everyone who is not in it yet, at a role no higher than your own in either workspace; and the Share chat and Use <parent>'s roles, teams and divisions switches, the same switches as inside the sub-organization (the second still asks first, with the count of projects affected). Nobody already in the sub-organization is changed, and a pending or deactivated membership there is left as it is. If the people you chose would not fit the sub-organization's seats, nobody is added and Noots says how many would fit. You need to be a member of the sub-organization, and changing anything needs permission to manage members in both workspaces. Structures, files and milestones are shared down from their own screens.

In a sub-organization, Administration → Organization has a switch: Use <parent>'s roles, teams and divisions. It is off by default, and changing it needs permission to manage members in both workspaces. With it on, the parent's custom roles, teams and divisions show in the sub-organization read-only, marked Managed in the parent, and any change the parent makes shows up straight away. People in the sub-organization are placed on those teams and divisions and given those roles under Roles & Teams, and each of those places applies only inside the sub-organization: it grants nothing in the parent, and nobody's place in the parent grants anything in the sub-organization. The parent's admins decide what those roles allow, in the sub-organization too. Before the switch turns on, Noots says how many of the sub-organization's projects are shared with its own teams: those teams are set aside while it is on, so people who reach a project only through them lose that access until it is shared with one of the parent's teams. The sub-organization's own roles, teams and divisions are kept while it is on and come back when it is turned off; nothing is deleted either way. Turning it off asks first too, with how many of the sub-organization's projects are shared with the parent's teams: people who reach a project only through those teams lose that access until it is shared with one of the sub-organization's own teams.