I assume by "survivor" IRA, you are the beneficiary of an IRA. In that case they can't be combined and the rules are completely different.
You can only combine "like" account. If you have one IRA in your name, you calculate and take the RMD according to the normal rules.
If you also have a beneficiary IRA, the RMD for that is calculated separately, and using a different formula. The rules are also different depending on what year the previous owner died, what your relationship was, and what your ages were. Can you provide those further details?
