Genericity and XML-Schema

Hi,

I know someone has probably asked this question before, but is
genericity/polymorphism supported in XML-Schema?  For example if I have a
complex type for <list> and want to later on create a list of addressess
or a list of blood pressures.  Is genericity anything more than simply
creating a complex type which extends the <item> in the <list> as an
address or as a blood pressure?

thanks,  Andrew