This groovy script will return a list of DeviceGroups based off a given Asset's serialnumber.
import com.axeda.drm.sdk.device.*;
import com.axeda.drm.sdk.Context;
Context sysContext = Context.create();
DeviceGroupFinder dgf = new DeviceGroupFinder(sysContext);
DeviceFinder devFinder = new DeviceFinder(sysContext);
devFinder.setSerialNumber("[your serialnumber here]");
Device myDevice= devFinder.find();
dgf.setDeviceId(myDevice.getId());
List<DeviceGroup> allGroups = dgf.findAll();
allGroups.each
{ group ->
logger.debug(group.getName());
}