The best website about SEPP is http://72t.net/
. Bookmark it. It's full of good info.
If you look through the FAQs, you'll see this:
Q. Do All IRA Accounts have to be combined to determine the amount of the distribution?
A. Individual retirement plans do not have to aggregated for purposes of calculating these payments. If a taxpayer owns more than one IRA, any combination of the taxpayer’s IRAs may be taken into account in determining the distributions by aggregating the account balances of those IRAs. PLR 9050030
Q. Can a portion of an IRA account be excluded from the calculations?
A. No, the entire account balance in each of the pertinent IRA's must be taken into account. A portion of one or more of the IRAs may not be excluded in order to limit the periodic payment to a predetermined amount. PLR 9705033
Q. If I include more than one account, which accounts do I use to make the payments?
A. If two or more IRA's are used in determining the substantially equal periodic payments, the distributions need not be made from all of the included IRA accounts. The distributions may be made solely from one of the accounts, or from a combination of the accounts. PLR 9705033
You have considerable flexibility.