Hi and welcome to HC, Scoobs! So sorry to hear about the passing of your previous hammy Scoobs, but congrats on getting Teddy and Bear. As many have already previously stated, unfortunately the pet store owner had totally misinformed you. Even though you may love for your two new hammies to become lifelong friends since they are littermates, they will inevitably end up killing one another if kept together. Therefore, I would definitely separate the two as soon as possible and get another Syrian appropriate-sized cage so they can be housed totally separately. It will not be alright for them to only be separated by a divider since one could possibly escape to the other side without your knowledge and they can also smell and hear one another causing severe stress. I have family that have two Syrians, and they keep them on totally opposite sides of a large room. If that is possible, I would strongly suggest to do the same. I would also purchase separate wheels, water bottles/bowls, play toys, etc. so they don't have to share these either. I hope that you are able to still keep both Teddy and Bear separately since I know that you must have fallen in love with both already. Sorry that you weren't aware of this prior to buying each hammy, but if you ever have any other questions, please never hesitate to ask. Good luck with everything, and I look forward to seeing you around at HC, hearing more about your Syrians, and of course seeing lots of pics whenever they settle in more. BTW, Eros waves to her new friends Teddy and Bear.
Edit: I just noticed that you were posting while I was typing this post. I definitely would not connect the two via a tube either. Sorry! If Teddy enjoys tubes a lot, I would just find a way to incorporate them in his cage layout without involving Bear's cage at all. I hope that this helps.