Nested fields without fields_for

Question

Well, I have one has_many :through relationship between a Project and a Material models. A Project is composed by X Components(x is the number of sub-divisions that Materials has, and Components are the junction model for Materials/Projects), and I want to filter the other sub-divisions in each collection select, like here :

The problem is that I cannot put all the fields for each sub-division in the fields_for form, because it would repeat the fields for each instance of Component created, and that's not what I want. Is there a way to set up the nested form without fields_for?

Material Model :

Project Model :

Thanks for the attention!