AS, login, filter

Hi all,
I need a help to solve problem with ActiveScaffold,
Imagine that you have a list of companies, each company has a list of
products. If I’m administrator of some company and I want to edit my
products I also can see(not edit, editing/deleting is possible to
disable) other companies products.
I need to use activescaffold for displaying/editing only data that
connected to company that loggined by current user(of course product
model has a company_id, by I don’t know how to filter this data).
Thank you for any help and advices
Have a nice day!