@Cow:
The Europe rulebook is indecisive in their wording about it, while the pacific rulebook says you must offload everything.
Thing is I have units from anzac on an american transport so we want to unload 1 unit only… which I thought was legit… till it got questioned.
It depends on when the units were loaded. If it’s a combat move and the units are loaded during the combat phase, then all units that loaded MUST unload (in general, you cannot move a unit as a combat move unless it results in combat - exceptions to naval & scrambling, but that’s it). That also means the unit MUST amphibiously assault - it unload in a friendly territory, and if you didn’t have a hostile territory to unload it into, it wasn’t permitted to be loaded in the first place.
If one of the units was loaded during a previous noncombat, and one was loaded during combat, then the one loaded during combat MUST amphibiously assault. The one that was already aboard may unload as a combat move, but if it does not it cannot unload at all during noncombat (as the transport was used during combat).
If both were loaded during noncombat and are both being unloaded during noncombat, then it’s up to you. But they cannot unload to two different territories.
In your case, both were loaded as a noncombat in a previous turn. One or both may be unloaded to amphibiously assault, but once one unloads during combat, the second is not permitted to unload during noncombat.