In 'Enter Person' form, can multiple email addresses be used for one person?

Hi there,

I tried to enter an user and he likes to have system notifications sent to two different email addresses.  I entered the two addresses, separated by a comma, but it seems like not working.  Please advise if this is the correct way to do it or it not possible to use multiple email addresses in that form/that field.  Here is one example:

Thanks,

Ning