Algorithm / Code to find dependency and build row column wise hierarchy model using VBA

[SAG91]

Suppose I have two columns ColA = Calling programs and ColB = Called programs, now I want to build a hierarchy between calling and called program and print them with the calling dependency lvl column as below.

Note:

1. Calling program for which called program is SPACES, is the initial program for a new branch.
2. Output representation can differ, but it has to be in row and column only.

Input columns:

COLA COLB

AAA
AAA BBB
AAA CCC
BBB
BBB CCC
CCC DDD
CCC GGG
CCC HHH
DDD
DDD III
DDD MMM
EEE
EEE BBB
EEE FFF
EEE JJJ
EEE KKK
FFF
FFF LLL
FFF MMM
FFF NNN
MMM OOO

Output:

COLA(Initial) LVL COLB(Calling) COLC(Called)
AAA 1
AAA 2 BBB
AAA 3 CCC
AAA 4 DDD
AAA 5 III
AAA 5 MMM
AAA 6 OOO
AAA 4 GGG
AAA 4 HHH
AAA 2 CCC
AAA 3 DDD
AAA 4 III
AAA 4 MMM
AAA 5 OOO
AAA 3 GGG
AAA 3 HHH

BBB 1
BBB 2 CCC
BBB 3 DDD
BBB 4 III
BBB 4 MMM
BBB 5 OOO
BBB 3 GGG
BBB 3 HHH

DDD 1
DDD 2 III
DDD 2 MMM
DDD 3 OOO

EEE 1
EEE 2 FFF
EEE 3 LLL
EEE 3 MMM
EEE 4 OOO
EEE 3 NNN
EEE 2 JJJ
EEE 2 KKK

FFF 1
FFF 2 LLL
FFF 2 MMM
FFF 3 OOO
FFF 2 NNN

I tried, but I am stuck at LVL 4 and the recursive loop. Please suggest