This article explains how can you hide some of the tickets from general searches. For example how to create a search, so that only certain teams can only see incidents for their own teams.
To restrict the search:
1. Go to Configure Applications > Users and Roles > Roles and Permissions.
2. Select a role. For example, the ChangeManager role.
3. Select the object in question, and click Edit under the right-hand Access column.
You will use the following to indicate that 'When logged into this role, a user will only be able to see incidents for which the Team of the Incident is the same as their team':
Note: If the user has multiple roles and you want to enforce this search limitation across multiple roles, then you will need to configure the restriction in the same location, for each desired role.