You can have different carriers within one and the same PBX. In your mobile you can have any operator, but if you want the MEX feature you must have a fixed number and mobile number from the same operator. The same person must therefore have the same operator on his fixed line number and his mobile number if MEX is to work. However, different people can then have different operators within the same exchange.
Our exchange services are completely independent of which carrier you choose. You can choose to use us at Dstny as a carrier or one of the other major carriers. Regardless, our services will work the same way. In addition, you can mix carriers within the same exchange. It does not get smoother than that!