Can't you stack your roach enclosure that you are using now?

I see no problem with putting your hissers and your Dubias in one container the only thing you have to think about then is you will end up with a container that needs to be a bit bigger than what your tanks are know.
And then to add the other "million roaches" into the container with them you will need a really big container.
like 110 liter plastic bin.

I would advice that you keep your roaches separate, and get your self some plastic bins and stack them, this will save you on floor space and allow you to use wall space.
Builder warehouse is selling some nice black Addis bins that seem to lock pretty secure.
and you get different sizes of the bins.



On a stage I had over 100 Dubias in an ice cream tub, on substrate with bark and they kept on breeding. takes up far less space.





The blue bin is a 12liter container, I had my Dubias in the container for some time over 300 odd on substrate until they got moved to a bigger container.
They are nice and small containers and does not take up much space