Align forms columns

Hi all,
i have a page where i have 2 Form, and each form has it's properties. The most long property-caption determine the captions column widht in the Form, so each form has it's own width.
The graphic result is ugly, and it would better if the two Forms share the same column width.
How can i accomplish this ?

The problem come from my dataModel:

ITEM {
   FOO{
      a,
      b,
      c
   }
   BAR{
      a, 
      b
   }
   a
}

where ITEM is the object i need to show in the page, FOO and BAR are two sub-object and a, b and c are properties. I'm using a Form with FieldFactory and FOO and BAR fields are 2 Forms. I write this in case i'm in the wrong way and someone knows a better method to show complex field in forms.