It is actually not entirely true that it is vACC based. The entity that publishes the sector file should sign up at GNG. In most cases on VATSIM this is a vACC, since each vACC has its own sector file. In other cases this even is a FIR, e.g. Germany, each FIR publishes its own file, however their files are combined on one download page: http://files.aero-nav.com/EDXX
So if you want to have one sector file for the whole division then you could sign up the division. But honestly I do not believe that this would be a very good idea, as the file would become huge and take forever to load, further more stretching from something like 35°N to the north pole leading to difficulties when displaying, probably huge differences in magnetic variation...
Usually the person responsible for the creation of the file signs up and is the "owner" of a vACC within GNG. This way he can set and revoke read/write rights of his vACC for new people, can register beta tester for his vACC and so on. Also we will contact this person in case of any abnormalities and neighboring vACCs will most likely contact this person if they need to discuss something, e.g. airspace borders or COPX. Sometimes it is also the vACC Director who signs up, it does not matter too much for us who it actually is, but it makes things easier if it is someone actually working with the file instead of VATGOV1 for the whole planet.
I do not know why you exactly want to register the division. Is it that all files of your Division are on one download page? This could be easily done. Or do you want to be the owner of all VATRUS vACCs within GNG? Also this can be done, with the drawbacks mentioned above. Still someone would need to register each individual vACC (or each entity that publishes a separate sector file), either you or someone in each vACC. We can change ownership of the vACC to you thereafter.