help needed with generics

Hi

I need to declare a variable that will store  (system.collections.objectmodel.) collections of different types
e.g. collections of object a, collections of object b

I am then binding this variable to a datagrid.

so far the only thing i can get to work is to declare my variable as type object. i then bind this to a datagrid and everything seems to work ok. i initially tried to declare the variable as collection(of object) but i got casting errors when i tried to assign a collection of a different type of object to it

before i get too carried away that this 'will do' as a solution, can anyone see any problems i might face later down the line?

thanks
andrea