How to add SYSOP user role to those permitted to view all tickets?

Following up on https://premium.wpmudev.org/forums/topic/support-plugin-assigning-tickets-to-non-admin-users?replies=5#post-1108526

I have a custom user role called Sysop. I do not want all users to be able to see all tickets, but I do want all Sysops to be able to see all tickets along with Admins.

Ash recommended a simple solution for adding Sysops to the "assign to" drop-down and I am looking for a similar solution to allow Sysops to view all tickets.

Right now Sysops can only see their own tickets, and those assigned to them.

Thanks in advance,
Mark.