I did exactly what "onehandoneheart" did with my CO lines. I have a main number and 4 other "random" numbers in a hunt group and didn't want these other numbers going out as our number on CID so I called AT&T and they changed lines 2-5 to "terminals". (term. 0001-0004). My hunt order is still main number, term 0001, term 0002, etc. It appears that AT&T has accidentally programmed your lines for a UCD (uniform call distribution) type of arrangement. You need to explain to them that you want your lines to hunt in a particular order (I.e. main number, term 0001,term 0002), not uniformly.
There seems to be some confusion with terminology here too. A "terminal" line is simply a POTS or trunk line (LS or GS) that is associated with a main number but has no individuality. It cannot be called directly. It almost always is in a hunt group with a main number and other terminals making up a "hunt group". There are a few different types of "hunting", "terminal"and "circular". "Terminal hunting" starts at the main number and hunts through all the lines until it finds an idol one and processes the call. A "Circular hunt" does the same thing but will "wrap around" from the last line to the first line if need be. A "terminal line" and a "terminal hunt" are two different things even though most "terminal lines" are arranged in a "terminal hunt" sequence.
Is that confusing enough?