Hy,
I have two libraries in Sharepoint. the first one is called Change Driver (CD) and the second one is called Work Order (WO).
The Change Driver lib contains Infopath forms like CD1, CD2,...
respectively, the Work Order lib contains Infopath forms like WO1, WO2,....
Any CD can have 1, 2, 3 or more WO affiliated to.
then, in my CD form ...