Purity: Combining Intentions for Recommended Ghusls
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 636:
It is sufficient for one to perform one ghusl with the intention of several different recommended ghusls, except for those ghusls that have become recommended for one to perform on account of having done something, such as the ghusl for having touched a corpse that has been given ghusl. For this type of ghusl, the obligatory precaution is that one must not suffice with performing one ghusl for several ghusls.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)