As a brand new PGY-1, this is a bit of a far-off concern, but can someone break down for a noob (or point to an appropriate thread about) all this partnership/buyout/group mumbo-jumbo?
First KEY concept that many residents don't understand, if you are working in private practice you are the owner of a small business. The concept of salary, benefits, etc is misplaced. You are no different financially from a guy who owns a dry cleaner or a McDonald's. You have a product you sell, you have expenses to pay and you keep what is left over.
In most groups, you begin as an employee of the group - in which case you are paid a salary, get bonuses, have benefits, etc. After some period of time, you can become a partner. (In most cases you are not a true partner but a shareholder in a corporation) As a partner, you will typically receive some base salary fairly similar to what you made as an employee. Periodically (monthly or quarterly) the practice balances its books, takes any profits and distributes them to the partners. If the practice has a bad year for some reason - it comes out of the partners bonuses.
Someone who wants to own part of an anesthesia business has to compensate the owners somehow. The typical way to do this is to work at a reduced wage for a period of time. 1-3 years is fairly common. The buy-in in this case is hidden. Say they pay you $250K but you bring in $290K to a 10 man practice. You are essentially paying each partner $4K/yr for your share of the business. After partnership you'll presumably make $290K.
In the situation described by the OP, you make partner (or don't) after 1 year and then pay the group $40K/yr for the next two years.
The buy-in to a group, either through a formal process or a parternship track at reduced salary, varies substantially depending on the desirability of the group.
A group whose income/work mix is much higher than average in a desirable location will command a substantial buy-in. There are stories of 5-7 year partnership tracks at low salaries in some places.
A group with an average income/work mix in an average location will have a much shorter track - 1 to 2 years at a good salary.
A group with substantially below average income/work mix and an undesirable location will not be able to retain people and will generally resort to locums, an AMC (anesthesia mangament company - a multisite anesthesia staffing corporation) or hospital employment. These are the places that offer "partnership from day one." What that means is that all the anesthesiologists are equal in that they are all employed by someone else who reaps the overall profit (or loss) from the group and you are an employee, not a business owner.