Control HomeKit enabled device with multiple iOS devices

Is it possible to have my iPhone and my wife's iPhone both be able to control our HomeKit enabled devices? I have 2 Ecobee3 HomeKit enabled thermostats and I set them up on my wife's iPhone but my iPhone cannot also seem to register them for HomeKit and while hers is able to control them with Siri mine cannot. We have a family iCloud account -- if the devices can only be controlled by a single iCloud account this will be a major problem going forward since it defeats the purpose to a great extent if not everyone in the family can use home kit to control the devices once location based control and some other advanced triggers are made available.