Distribute amount with staggering and based on priorities

[Qete_ARG]

Hi guys, I am trying to find yout how to solve this but I am not being able to do it. I also searched but I think I am not using the right words on the search box (sorry for my english).
I need to distribute an amount between many contracts, filling first the ons with better priorities than the others.
Here is my example:
__________________________________________________________________________________
|Total Qtty ...........|......Max qtty per contract...|...Priority.......|..............What the formula should do..|
|to be distributed..|..........50000....................|..3................|.........................53333.....................|
|.........................|..........100000..................|..3................|........................106667....................|
|300000..............|...........80000...................|..2................|..........................80000....................|
|.........................|...........30000...................|..1................|..........................30000....................|
|.........................|...........30000...................|..1................|..........................30000....................|
| _________________________________________________________________________________
................................................................................................................. 300.000 ................|
If someone could help me I would really appreciate it.

 

[veryamusing]

Something like this? Think about it like a waterfall...

 

[Qete_ARG]

Thanks a lot! How is it that I didn't realize how to do it?
Really appreciate it!
Miguel