glowingangel

Thank you Aaron2020. In essence I concur with what u have suggested but I used the wrong terminology when I said join should have been split.
Your breakdown is on point.

My brother from Pakistan,
No reason to leave your children behind. Simply divide the family between the petitioner and the Joint Sponsor.
The petitioner makes $48,665. That is enough for a household of 7. Since petitioner has a household of 3, he/she can be the I-864 sponsor for up to 4 immigrants.
The JS makes $42,000 which is enough for a household of 6. Since he has a household of 1, he can sponsor up to 5 immigrants.
Divide the immigrants between the petitioner and JS.
There is enough income for all of you to immigrate. It would be extremely foolish to withdraw the DS-260s.
Best of luck.
Your brother from Vietnam.

No. The petitioners can only combine income with household members. The petitioners can not combine income with Joint Sponsors.

Household of 3 + 5 immigrants = 8. No it's not.
Find another joint sponsor for some family members.

You should be able to another joint sponsor. You can have sponsor A for you and wife and child 1 and another for the other 2 children. Each sponsor must make enough to support their family and people that are immigrating. A family group can have no more than 2 total joint sponsors

I think this might answer your question
i-864p.pdf

5 immigrants + sponsor = household of 6. The required income level for a household of 6 is $40,712. So an income of $42,000 would be sufficient.