[support] Menu navigation block

Hi, Assuming I have a menu "Primary Links" with the following items: -- Page 1 ---- Page 1.1 ---- Page 1.2 -- Page 2 ---- Page 2.1 ---- Page 2.2 It is easy to put the "Page 1" and "Page 2" at top of the page. But now, when I click in "Page 1" I want to have a left column block, showing only the child menus. This is similar to what the book module does, but instead of using a "book structure" it should use the "menu structure". Anything done to accomplish this? Regards, Fernando Silva