you can use the auth section of forum – profile – tabs and menus to control access to a tab or menu… you cannot directly do it by users though as its an auth (permission)… so you would put in there an existing permission (see forum – permissions – manage permissions) to see your current list… take a look at the signature menu under profile and you will see it already checks the auth for using signatures…
I suspect that wont give you what you want so you would need to use the permissions api to create a new permission… thus you could create a permission for each menu and or tab and then only grant that permission to specific usergroups that you want to be able to access that menu or tab…
a new permission is easily created by using calling the create auth function… here is its prototype:
function sp_add_auth($name, $desc, $active=1, $ignored=0, $enabling=0)
you could do that in your sp theme spFunctions.php template file…
I have thought about adding a create permission api in the admin, but its not there now…