Save it in a global variable, like:
Code:
new g_Menu[33]
...
public menu(id)
g_Menu[id] = menu_create(...)
Edit: You don't need to create 33 cells and save the menu for everyone, that's just a solution if you want custom menus for every player out there
Code:
new g_Menu
...
public menu(id)
g_Menu = menu_create(...)