def get_contact_groups(options = {})
      request_params = {}

      request_params[:ContactGroupID] = options[:contact_group_id] if options[:contact_group_id]
      request_params[:order]          = options[:order] if options[:order]
      request_params[:where]          = options[:where] if options[:where]

      response_xml = http_get(@client, "#{@xero_url}/ContactGroups", request_params)

      parse_response(response_xml, {:request_params => request_params}, {:request_signature => 'GET/contactgroups'})
    end
def get_contact_groups(options = {})
      request_params = {}

      request_params[:ContactGroupID] = options[:contact_group_id] if options[:contact_group_id]
      request_params[:order]          = options[:order] if options[:order]
      request_params[:where]          = options[:where] if options[:where]

      response_xml = http_get(@client, "#{@xero_url}/ContactGroups", request_params)

      parse_response(response_xml, {:request_params => request_params}, {:request_signature => 'GET/contactgroups'})
    end
Retreives all contact groups from Xero

 Usage:
   groups = gateway.get_contact_groups()