Arrange your data and headers as shown:
p_n desc price Au Bu Cu Du
23 valve 1.00 1 1 0 1
32 pump 2.50 0 1 1 2
3 plc 6.75 1 1 1 0
45sd sw 9.00 0 0 1 1

select
Du
p_n desc price qty rsel set2
32 pump 2.50 2 2 1
23 valve 1.00 1 1 2
45sd sw 9.00 1 4 3
4

Select the data under p_n, desc and price (12 cells) in the first
array and
Insert Name Define array1
Select the data under Au, Bu, Cu, Du (16 cells) and name it array2
Select the Au...Du header and its data (20 cells) and
Insert Name Create Top Row
Repeat for the 2 cells (select, Du), the 5 cells (rsel,2,1,4,blank) and
(set2,1,2,3,4)
Extend the series of numbers of set2 to equal the number of parts (n).
Create an array the size of array2 and fill it with
=(RAND()-0.5)/100+1
Copy Paste Paste Special Value, Multiply to array2.
Redo after updates.
Enter this formula into rsel and copy down n times:
=IF(set2COUNTIF(INDIRECT(select),"0"),"",
MATCH(LARGE(INDIRECT(select),set2),INDIRECT(select ),0))
In the results array, under p_n, desc, price (12 cells) enter
=IF(rsel="","",INDEX(array1,rsel,))
Under qty, enter and copy down n times
=IF(rsel="","",ROUND(INDEX(INDIRECT(select),rsel), 0))
Under select, change Du to another unit as you please.