I am the leader of my own crew of high-level characters. We have Necromancers, Brawlers, Assassins, Mind-Readers, etc. Because the world is always about to come to an end, they mostly wander in pairs going where they are needed.
However, I worry that an emergency may happen at headquarters, on such a scale, I'll need them all here immediately. Like, for example, last week, a Tarrasque decided to rampage nearby. That sort of emergency.
How can I arrange it?
I thought of mixing a Contingency with Teleport, but I cannot do that for others, and not all of them are high level spellcasters. Is there any way I can do this?
Let's assume preparation time is practically unlimited, as well as resources (we make thousands of gold per adventure, and just invest it in the realm). Also, I can probably hire strong casters from whatever class to cast or prepare spells for this (so no class requirements here). Any officially published materials are valid sources.
But once the system is in place, it needs to be able to be activated on as short notice as possible, for example by pressing a big button which may be in a fixed location at HQ.