If I understand what you are trying to do correctly, this is pretty easy to achieve:
Simply double-click on each of your fields in the first row and set the default value to the same thing but specify that the first row has to be used:
1. In the data source tree, double-click on the field of interest (for example, /my:myFields/my:data/my:row/my:address)
2. Click on the "Fx" button next to the value textbox
3. Check "Edit Xpath (Advanced)"
4. Type in the xpath to the first occurance of the element (in this example this will be /my:myFields/my:data/my:row[1]/my:address)
5. Click ok, then uncheck the "Update this value when the rest of the formula is recalculated" checkbox, ok again
You're done! Now every time you insert a new row, it will have the same address as the one in the first row.
Note that if you do not uncheck the checbox in step 5, the other rows will ALWAYS have the same value as the first one. This is usually not the desired behavior.
You can find a working example here:
http://www.infopathdev.com/files/folders/community_uploads/entry20327.aspx
Hope it helps!
David Airapetyan / Software Services ArchitectQdabra® Software / Streamline data gathering to turn process into knowledge