As you know, according to the verdicts of some of the grand jurists, payment of khums to a marja other the marja whom the payer is a Muqallid of should be in accordance with certain rules and criteria as shall be mentioned below:
If a person wishes to pay the portion of Imam (Sahme Imam) from his own Khums dues to a Mujtahid whom he does not follow, he will be permitted only when he knows that that Mujtahid and the Mujtahid whom he follows spend Sahme Imam (a.s) in the same way.
Ayatollah Khoei and Ayatollah Tabrizi (may Allah bless them) say: "As an obligatory precaution, he must obtain the permission of the Mujtahid whom he follows."
Ayatollah Bahjat: If he spends it on the same purpose in quality and quantity as required by the Mujtahid whose Muqallid the payer is, (it is permissible).
Makarem Shirazi: If a person wishes to pay the portion of Imam (a.s) from his own Khums dues to a Mujtahid whom he does not follow, he can pay him only when he knows that that Mujtahid and the Mujtahid whom he follows spend the portion of Imam (a.s) in the same way.
Shubairi Zanjani: If a person wants to pay the portion of Imam (a.s) from his own Khums dues to a Mujtahid whom he does not follow, he can pay him only when he knows that that Mujtahid spends the portion of Imam (a.s) on purposes that are allowed by the Mujtahid whom he follows.
It should be noted that late Ayatollah Fazel Lankarani's fatwa is different from the fatwa of other grand jurists: In his view, both of them (Sahme Imam and Sahme Sadat) should be given, at the present time, to the Mujtahid whom he follows or be spent on purposes as allowed directly by his office.[1]
As for which maraje' (jurists) spend khums in similar ways, the Mukallaf (duty-bound) himself should identify them. Of course, the offices of the grand jurists can help him in this regard.