I'm new to Zoho so I apologize in advance if this happens to be a silly question.  

I run a basketball club and I want to import my member list, but the system i'm importing from allows the member to register more then one player in single instance (siblings). The system creates separate forms for the all of the registrant dat, but allows the parent/guardian to use the same email address for each registrant in the group. This makes sense for the user entering the details for kids from the same family.  Each registrant, even in a group registration of 2 or more, does have a unique registrant ID.

I'm facing the problem of duplicate records based on the email address, which I'm worried will creates a problem for future mass mailouts or campaigns, because I'm can't find any evidence that Zoho will not send to a duplicate address in a campaign like.  I need to keep records of each member knowing that 2 siblings records are almost identical except for the names.

Can anyone suggest the best way to manage this and how i can ensure that when I send an mass mail that the mother of 3 registered players wont get same email 3 times? Is there a better way of 

Anxiously waiting... 

cheers,

Greg