It is doable but would probably be more suited to using access.
In the absence of that, you could use vlookups.
e.g. when you choose a company from the drop down, in the address cells have:
(I'm assuming 600 addresses but you can increase that number). That will bring back the street.
You then put a similar formula but change the "2" to be 3,4,5 etc. to get back the other bits of the address?