He intentado a partir de una tabla de ipart de 8 filas hacer un ilogic y no me sale siempre da el mismo error (object reference not set to an instance of an object)
I think this is what you want.
Code for the rule, see attachment.
Save your I-part as an other part.
Then you open the part and delete the structure from the I-part,
so it wil be a normal part.
Then you open your rule en delete everithing in it.
Then you past de code from the attachment into your rule.
(I now that the code can be write better, but this wil do the trick.)
When you open the form and select a brida it wil change.
in the beginning it can have a slow start.