If all show withholding, you can combine those from the same plan having the same code in box 7 and marking of the IRA/SEP/SIMPLE box, but you must then mail your tax return and include the required printed copies of the Forms 1099-R. Even though TurboTax will permit you to e-file, doing so would cause the combined Form 1099-R to differ in detail from the individual Forms 1099-R provided to the IRS by the payers leading to potential problems processing your tax return.
