routing based on db item values

How to enable routing if agreement parameter equals 1 to agreement and
othwerwise to options ?

See example:

  def select
    @imitem = Imitem.find(params[:id])

if (@imitem.update_attributes(params[:agreement]))
redirect_to :action => 'agreement', :id => @imitem
else
render :action => 'options', :id => @imitem
end
end