shared menus on all multiple pages - Joomla! Forum - community, help and support

i'm trying build community site has similar menus/tabs across
multiple pages. not seem practical for
design similar menu items every page. example, classes 1-8 the
pages , subjects (maths, english, history, science) top
menus/tabs found in every page/class. when user chooses class, he/she has similar menus(subjects)
at same menu location. details change on every
menu when select different class. upon adding class(1-8) the
menus/tabs assign themselves.
if have better solution problem, love hear it.
i wondering if theres way add dropdown combo box for
classes, such user drop down list choose instead of
a static list.
thanks in advance