InfoPath Dev

All,

I've a repeating table with a drop down list of options and another column for attachments.

Depending on another answer on my form, The users have to attach X number of attachments. They have a list of options.

How can I validate that that I have a minimum number of attachments i.e. 2 and that each attachment is of a unique type ? 

Thanks

W 

 Thanks Hilary, but this is no longer required...Team is making me move to the dark side..N......x