Connect staged group Nexus negotiations

docs/OPTIONAL_ALLIANCE_VICTORY.md

@@ -1,5 +1,24 @@
 # Optional three-stronghold alliance victory
 
+## Group Nexus negotiation — 28 October 2026
+
+**Integrated groundwork, not a selectable game mode.** In a staged Basic
+classic-faction Nexus with the group ledger present, a pair member or an
+unallied entrant can propose adding the entrant. Every participant must
+explicitly agree; a decline cancels the invitation and preserves the pair.
+Each proposal has a fresh event and revision, and an unanswered invitation
+holds the Nexus. Leaving a three-member group retains the other pair and its
+original edge age. Pair offers involving the newly formed group are cleared.
+The staged table renders the group controls and minimal bots can answer.
+
+Unanimity, cancellation, the pending-Nexus hold and the surviving pair are
+provisional online procedures, not publisher rulings. This scope excludes
+expansion decks/factions, Advanced, optional modules, live Truthtrance
+commitments and pledged aid. No lobby creates the group ledger: faction ally
+benefits, group funding and other interactions must be connected before any
+player can start the printed larger-alliance option. The separate unlimited
+alliance variant remains missing.
+
 **Prototyped / Partial — 28 October 2026.** The host can select a shorter
 two-member alliance game in the lobby. With at least three physical
 controllers, allied factions need three distinct qualifying strongholds