Okay. So all tickets, whether they have been transferred to a Tier 2 group or not, still need to be seen by the Tier 1 group.
Can the Tier 1 group not see all tickets today? If yes, then you could simply give them a scoreboard node showing all unresolved tickets. If no, have you implemented some data partition that prevents them from seeing the tickets if they are not a member of the group to which the ticket is assigned?