You can! The base package that is included in your weekly rental amount allows online access for 3 devices.
However if you need more that this the new 4Connect-Plus service ASK4 will be able to provide secure connectivity between multiple devices. This means you will now be able add additional devices to your account, use a wireless printer, stream content to a Chromecast or Apple TV and more. This service is available for just £25.
For more information go to portal.ask4.com.