Saving Value To Variable? (update/make Table Query)

I am trying to create a table to show the parent/child relationships between assemblies, sub-assemblies and detail parts. The table I start with has 2 fields a "Part Number" and an "Indenture".

Please forgive all the periods, couldnt think of how else to seperate the values to depict the tables.

Example:
IND..PN
00....A
01....B
01....C
02....D
03....E
03....F
01....G
00....H
01....I
02....J

I can get the first step to completeing the new table of parent/child relationship like this:

PN....00....01....02....03
.A.....A
.B....."".....B
C......"".....C
D......"".....""......D
E......"".....""......"".....E
F......"".....""......"".....F
G......"".....""......""....G
H......H
I......""......I
J......"".....""......J

Where "" are null values

My problem is making it so that every part number has its own array, aka [family tree], so that for part "F" the table would hold "A,C,D,F"

I though an update query where for example:
*"Zero" is a single field string.

IIF([00]<>null(), Save [00] to Zero, Write Zero to [00])

Would work but have been unable to find any information about passing a field value to a variable for later use or comparison. I would have already done this in excel if the table had less that 65000 records.


Example of final table:

PN....00....01....02....03
.A.....A
.B.....A.....B
C......A.....C
D......A.....C......D
E......A.....C......D.....E
F......A.....C......D.....F
G......A.....C......D....G
H......H
I.......H......I
J.......H......I......J

Any help is greatly appreciated.
BsK