How use a One2Many as a domain on a Many2One inside another One2Many, all of it on a wizard

I have a Wizard wich start form has 2 One2Many lists.
The first one is related to a model.A
The second one is related to a model.B, but it has a Many2One field related to model.A.
I need to know how to use the first list as a domain of the Many2One inside model.B.