How can I check where my variable is from

I have a controller like this :

 def index
        @invoices = current_company.invoices.order(billed_at: :desc)
        @user_invoices = current_user.invoices.order(billed_at: :desc)
        @all_invoices = (@invoices + @user_invoices).sort_by {|a| a.created_at}.reverse
    end

In my view, I would like to separate the invoices from user and invoices, something like :

- @all_invoices.each do |invoice|
  - if invoice.user? 
    = invoice.id
    = invoice.number

But I don't get the how to know if my invoice is from the User table or the Invoice table, how can I check that ?