finding the correct syntax for special objects such as groups and cameras

I'm really having trouble finding the correct syntax for groups and cameras.

for instance this works on most generic objects but does not on a group
tmpStr = currenttime as string
tmpStr = substring tmpStr (tmpStr.count - 1) --rename the object with the current frame number prefixed
$.name = tmpStr + $.name

I want to copy rename and unlink a group from a dummy.

I got help with this syntax (thank you)
maxOps.cloneNodes (getNodeByName grp_list.selected) cloneType:#copy newNodes:&nnl --copy whatever was choosen group pulldown using grp_list variable from above

I found this code for unlink but it really just blows up my group

for o in grp_list.selection do for c in o.children do c.parent = undefined -- try to unlink from parent

I also am trying to get a list of just camera names. I can use the keyword Cameras but this gives me all the targets if they happened to be one.

Again I seem to be into objects that have multi levels.

Its just not obvious where to look in the documentation.
any help would be appreciated.

Where would this be covered in the maxscript documentation?