If you specify "*" as the column id (in Resources view) it will show all events (regardless of their resource id).

See also:

Availability

Availability of this feature in DayPilot editions:

LitePro
DayPilot for JavaScriptNo SupportFull Support
DayPilot for ASP.NET WebFormsNo SupportFull Support
DayPilot for ASP.NET MVCNo SupportFull Support
DayPilot for JavaNo SupportFull Support