List Pages, Child Of Problems

Hi, tried searching but to no avail.

I have a site page structure similar to:

-a
-b
–1
–2
—x
—y
—z
–3
-c
-d
–1
–2
–3
—x
—y
—z

names are not important here, thats just an example. i want to exclude some pages from my list, and for some, only include it’s children.

so for example i may want to exclude a, and exclude b-2 but include b-2-x, b-2-y, b-2-z.

i’ve been trying to do this like so:
wp_list_pages(‘exclude=5,43&sort_column=menu_order&child_of=37&child_of=38&title_li= ‘ )

this doesn’t work though… any ideas?