Reverse engineering algorithm for get keys

I have 2 groups of 4 byte and from this i have to get a key that have 6 byte.
Im trying to get the algorithm but i cant in any way.
The 1st group have only one bit different from the 2nd one.
Idk if i have to extract the 1st or the second key, but i think the 1st one.

1st group 4byte: 0x6339959F
2nd group 4byte: 0x6339959E

1st group keys:

0x38A39FE39EF5
0x296A852D73EA

2nd group keys:

0x39BF16EACF1A
0x28760C242205

i let a another group and relative keys:
group: 0x66CF0824
keys:

0x92252BCADB80
0x83EC3104369F