I have 3 different menus that I would like to show in the 'hornav' module position, depending on the assigment.

I would like one menu for the 'Home' page and another for another section of the site but assignments are not working - it's either all or nothing or I get two menus.
Am I trying to do something the template cannot do? I am using a module to display the menus rather than the default main menu assignments in the Header and Footer. Driving me mad.....

Any help appreciated