JOIN results of refcursor functions

Hi,

Is there any way to use INNER, LEFT and RIGHT JOIN between functions 
returning refcursor type.

Explain:

function1 as refcursor
function2 as refcursor

both functions return columns a and b.

can i join the results of these functions in such manner (or any other):

function3 as refcursor

select f1.a, f2.b
from function1 as f1 inner join function2 as f2 on f1.a=f2.a;

open f3;
return f3;

Thanks,

Milan Oparnica.