I found the following passage in Mark Sainsbury's 'Logical Forms'
If a collection of propositions is inconsistent, any argument whose premises consist of all but one of the collection, and whose conclusion is a contradictory of the remaining proposition, is valid (23).
This seems to be true for three propositions, or where only one of the collection is inconsistent with the others, but what about where there are multiple inconsistencies? Please could someone verify in which cases Sainsbury's statement is true.