Is it necessary to say both surat Al-fil and Quraysh in Salat to count as one Rukat?

I've read in a few places that in order to say either surat Al-Fil or surat Quraysh in salat both must be said in order for the salah to be valid as these surahs are very closley linked. So one would say Al Fatha, then go onto say Al-Fil then would proceed to say Quraysh (with the bismallah for each surat) before one can proceed to ruku. Is this true or is saying one or the other enough to proceed to ruku? Let me clarify, this is per rukat and not per salah. So Al-Fil is to be said, then Quraysh before ruku then on the second rukat you can choose another other sura (excluding Al-Fil and Al Quraysh)