Finding a Custom Model Method with Other Fields Using Ransack

Question

In my project, the properties belong to the titles, and I have my own model method (for example: "somedate") that retrieves a field in one of the related header entries. I use Ransack to search and sort properties and would like to include a field in my search form for my somedate method.

I am currently calling <% = property.somedate (id)%> in the search output table using the controller index method (for example, @search = Property.search (params [: q]) that I would like to search. I guess I need a form_tag, but I'm not sure how to handle somedate params after it is in the form. How do I do this?