InfoPath Dev

I was afraid of that with the current() funtion not working well in IP2003. I am a bit skeptical that rules would work in this situation as the repeating sections have fields that are based on other data fields of that instance, and a rule would set all values in a repeating section to the same value, which would not work.  EX: Sub-total of ...

IP 2003.   Price_per_kg is something I assume has to be a calculated default because it is in a repeating group.  If I use a rule on Material_Name, it sets all instances of Price_per_kg to one value.  The functionality that I need is to have (0 to unbounded) instances of "Raw_Material" with independant Material_Name ...

I am trying to figure out how to get the current item of a repeating group that is nested within another repeating group.  Can anyone help with the xpath for this? My structure in my InfoPath form looks something like this: Assembly_Item (repeating group) my:Part_Families (group) ns1:Purchased_Part (repeating ...