How to check whether menuitem is permissioned to logged in user(/user group) in VAP 7.3.

Hi,

I am trying to check whether a menu item has been permissioned to the logged in user(/user group).I am having two user groups. If i removed visibility for one user, the visibility is getting removed for the second user too. If visibilty is removed it is getting applied for all the groups.Please help how to acheive the above functionality using VAP api. This permissioning issue is critical for our production site to permission different navigation items(menu items) to different user groups.