I don't understand very well what you meant by "calling the various outputs, out1, out2, out3 etc" but to answer the title's question,
In order to access the nth output of any function you would have to first call nargout on that function's name and then insert its output into a cell of preallocated size. Sample code below,
n = 5;
nout = abs(nargout('functionName'));
if n>nout
error(['n must be lower or equal than ',num2str(nout)])
end
out = cell(1,n);
[out{:}] = functionName(in1,in2);
nth_output = out{n};
This could be done inside any function that has functionName
in its path.