Generating a list of combinations (similar to Cartesian Product but more than 1 from each)

Long time reader first time asker!

I have a set of data and I am looking to generate a list of the combinations, I have found VBA and formulas but can't seem to get it right. It is similar to the Cartesian Product but rather than it being one from each list, there are multiples from each list.

For the example, for the data below I require 2 x West, 4 x North, 1 x South and 5 x East, however if a letter is used in one list it then cannot be used in any of the other lists (e.g. If D is in a combination as West it can't be also in there for North).

West	North	South	East
D	D	A	A
E	E	B	B
F	H	C	C
G	I		F
	J		G
	K		H
	L		I
			J
			K
			L

It will only ever be 4 columns (lists) or 2 columns (lists). With maximum number of elements in each column set as 10 and the total number to select never more that 5.

It would be ideal if the data output was each letter appearing in a different cell on a row as a combination. Most of the research and trials the output was generally a delimiter and each combination in one cell.

I have posted a similar thread (titled the same) on another excel forum but am unable to link it as a new user.

Any guidance is appreciated!