Joint Qurban share is not equal, Is It permissible?

What if the joint qurban  that can be compiled from seven people is not the same among the seven people?
For example, the price of a cow is 21 million rupiah. Five people joint venture for three million rupiah, while the sixth person joint venture 3.5 million rupiah. The seventh provides support for only 2.5 million rupiah.
 
Is the above example permissible? 
Shaykh Muhammad Shalih Al-Munajjid hafizhahullah was asked, "Can one of those who participate in the qurban joint venture provide less than 1/7 of the joint for cow sacrifice? Does it affect other shahibul qurban who join together? "
Shaykh hafizhahullah replied, "It is permissible to unite in a cow or camel as qurban for seven people. No one of the participants in the joint venture is allowed to be less than 1/7. This is if the goal is to sacrifice. If the intention is only to enjoy meat (not to make qurban), then it is permissible to join together as you wish.
Shaykh Ibn 'Uthaimin rahimahullah stated in the treatise of Ahkam Al-Udhiyyah gave the statement, "The goat is valid for one person. As for cows and camels, seven people are allowed. If the goats form a union of two or more people in their possession to be used as qurban, it is not valid. It is not legal to form an association except for camels and cows for a joint venture of seven people. Because remember udhiyyah (qurban) is a form of worship and qurbah (self-approach) to Allah. Because qurban is worship, it should be practiced in a way that is prescribed, namely following the time, amount, and method stipulated by the Shari'a. Summarized from Rasail Fiqhiyyah, p. 58, 59.
If one of those who cooperates with seven cows or camels is less than 1/7, it is not valid as a sacrifice. However, this has no effect on other shahibul qurban who are in the same group. Because it doesn't matter if it's in a beef joint venture, some intend to sacrifice, and some just want the meat (meaning: the intention of each participant is not the same). " (Fatwa Al-Islam Sual wa Answers, no. 111887)
Imam Nawawi rahimahullah in Al-Majmu '(8: 372) said, "You may associate in seven for camel or cow sacrifice. It could be that the union is one house or different houses. There could also be some in the union who intend to seek meat only. So those who intend to be made qurban are still valid, even though others intend to only get the meat. Likewise, including if the intention is for nadzar or qurban sunnah. This is the opinion in our madzhab (Syafi'i school) and also the opinion of Imam Ahmad and the jumhur (majority) of scholars. "
Imam Ibn Qudamah rahimahullah in Al-Mughni (13: 363) states that there are those who intend to sacrifice and some are only looking for meat,
لِأَنَّ كُلَّ إِنْسَانٍ مِنْهُمْ إِنَّمَا يُجْزِئُ عَنْهُ نَصِيْبُهُ, فَلاَ تَضُرُّهُ نِيَّةُ غَيْرِهِ
"Every one of them is considered to get the part that he intended and does not accuse the other's intentions."
 
Conclusion:Back to the problem of joint sacrifice of cows that are not the same, it does not include qurban because in the end one person ration is less than 1/7. This can be overcome by means of shahibul qurban who give a joint giving more to those who are less (patchwork) for their pleasure.
May Allah give understanding