Right, I thought that may be a quick fix to finding duplicate entries that your database may contain. I may have jumped the gun a little bit, and you not be needing that information. 
Here is a query that will combine all fields into one, when building the query go to the SQL View and input this code:
Code:
SELECT [Field_1] & "" & [Field_2] & "" & [Field_3] & "" & [Field_4] AS Combined
FROM Table1;
Where the "Table1" would be the name of the table that holds this data. Also, if you are needing a hyphen between each set of numbers you can add one between the "" between each ampersand.
Also, the word "Combined" where it shows AS Combined, I am telling the query to rename the output of Field_1, Field_2, Field_3, Field_4 as Combined. Whatever you change that word to, will be what your output will be named on the query.