[AccessD] Conceiting fields with same incident number

I have a table with 2 fields

 

Memo_Key  = ##_##   ##

 

Memo key is actually a text field but hay..

 

The first two places refer to a year.

The second two digits refer to an incident number for that year

Three spaces

The last digits refer to a line number in an additional text field

 

Memo_line is the matching text for that line. One incident can have multiple
memo lines.

 

 

If I do a left(Memo_key,5) I can isolate the incident numbers.

 

In rebuilding the database I need to get all the matching memo key items to
concatenate into a new memo field.

 

Any body know how I can do it?  

 

Thanks

 

Joe