You could try changing the channel, but the range of the hotspots won't be great. Definitely make sure they are on a different channel to your Hub.
I can't give you the exact steps involved as I haven't got a hotspot 600, but if you login to the hotspot there should be a menu option somewhere to change the channel. How to login is shown here http://btsupport.custhelp.com/app/answers/detail/a_id/45528/c/7187
It is also best not to clone the hotspot with your hub as it is then not obvious which device you are actually connecting to.