Currently, you can't make visibility segregation based on users or group.
There are some RFE on this like this one : https://2e4ccba981d63ef83a875dad7396c9a0.ideas.aha.io/ideas/R-I-255
At this moment, to allow this visibility, you must use the workspace:
Create a Workspace "A"
Create a Workspace role "WS Observer" with read only view
Create a Group "Observer on A" and assign your people that may view a specific tab of incident, even when not member of the incident
Assign the role "WS Observer" to WS "A" to the group "Observer on A"
Create a layout tab with condition visibility Workspace = A
This tab will only be visible in this workspace
All users' member of Group "Observer on A" will view the incident in this workspace, and the specific tab, even if no member of the incident.
Note : normal member of the incident will also have this tab visibility
If you want to restrict the visibility of some information to some people (users & group) only, the only way is to use private tasks.
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BENOIT ROSTAGNI
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