If the idea is to get as many high level characters on a single account, I would do it this way:

- Account A invites B, C, D, and E. That way all level grants go to A.
- Level one non-hunter (account A) and four hunters to 85 (I find hunters very easy to level quickly)
- Create two new characters on account A and grant levels to 85. Now you have three 85s.
- Rinse and repeat however works best for you (new group w/different classes, PL with account A, etc)
- Once you are done, transfer one of the hunters to account A.

That would give you one account (A) with as many 85s as you can manage with many different classes. Another way to do it would be to make a mixed-class team with a tank and healer to level to 85 via dungeons, then grant levels to two new characters and transfer the four other characters to account A, but that's an extra $100 instead of an extra $25.