We have multiple customer facing JSM projects, each of which has its own Portal used by the customer to view and respond to issues they have raised. Only the Support team have licenses for JSM.
We then have the development side of the business in Jira Software, with their own projects with items being worked on.
Occasionally staff on the development side will need to be able to view issues raised on the JSM side by customers. I'm able to achieve this by changing the 'Browse Projects' permission in the JSM permission scheme. This grants them view only access to the JSM items as expected.
The issue with this comes about when the development side then go to https://[OURNAME].atlassian.net/servicedesk/customer/portals (where projects available for you to raise issues in are shown). If the Browse Projects permission is set for the developers, they are able to see the customers portals. This causes an issue as we intend to have an "Internal IT Support" project for staff, which should be the only portal they have access to. We don't want internal staff being able to see and raise issues in a customers portal, only view the issues they have raised within Jira.
My question is; how can I set permissions so that staff on the Software side of Jira have access to view items within JSM, but the customer portals are not shown to them when visiting https://[OURNAME].atlassian.net/servicedesk/customer/portals?

Without Browse Projects set, the portal shows the above (which is correct, we don't want staff to be raising issues in a customer specific portal)

With Browse Projects set, staff can now access issues within the JSM project, but this also results in the customer portals for those projects being available to them.