osTicket is (in my opinion) a little under developed in the escalation side of things.
What we do where I work is a manual process.
I have three tiers here. Tier 1, Tier 2, and myself (Tier 3).
If a tier 1 tech cannot handle a call/ticket they let the user know that they are escalating it, They talk to tier 2 and then assign it to another (tier 2) agent. Then if the tier 2 cannot handle it they talk to tier 3 and assign it to them.
We discussed settings up departments or teams but I find that the simplest solution usually works the best.
