How to change device group after "Setup tool for E10A-USB Emulator"?

No, you cannot. Once the "Setup tool for E10A-USB Emulator" has been executed, a device group cannot be changed after.

Device Group Addition (License Tool for Device Group Addition) separately purchasable allows you to install additional device group to the E10A-USB emulator. Device Group Addition is software product allows another device group available with the E10A-USB emulator. It is offered in CD-ROM, and varies with the group of device. Since one E10A-USB emulator needs one license tool each, you need to purchase the Device Group Addition as the same number as the E10A-USB you want to have this installed.

When more than one device group is added to the E10A-USB emulator by this tool, the device groups can be switched among them according to the following steps. 

Click Start menu ->program ->Renesas High-performance Embedded Workshop ->Tools ->Setup tool for E10A-USB Emulator ->A name of a target device group -> Setup tool for E10A-USB Emulator

Execute this setup tool and follow instructions.