Prolog list of lists get all elements

Question

I have a lists of lists:

decide([[1,2,-3],[-2,3],[6],[4]],K). 

I want to return all the possible solutions pressing \';\'.

The rule is

Answer 1

Taking your other question as a starting point, simply insert your new requirements:

listoflist_member(Xss, X) :-
   ( Xs = [_] ; Xs = [_,_|_] ),           % new
   member(Xs, Xss),
   member(X, Xs).