What you want is a relationship between your tables
It sounds like the security table could have more than one entry for each person. If so, it will be a One-to-Many relationship. Here's how you implement that:
In youre new table, make sure you put a field in of compatible type to the EmployeeID (or whatever the unique identifier, Primary Key, is for your main table). If it is Autonumber there, make it Long Integer here. If it's Text, Text. This table gets its own Primary Key, but this is the field that tells it "this record is related to record XYZ123 on the main table." If it is a One-to-One relationship (you'll only have one Security entry for each person), then go ahead and make THIS field the Primary Key, No Duplicates.
Now go into Tools>Relationships from practically any window. Draw a line connecting the two matching fields in your tables. If you don't see your tables, right click on the blank space and select Show Table(s). The relationship should pop up and have either "One-to-Many" in the lower right, or "One-to-One". If it says "Indeterminate", you did something wrong.
Provided everything's going fine so far, check Referential Integrity and Cascade Update for the two records, and possibly Cascade Delete though I'd be careful about this one if you need to keep historical entries for auditing purposes.
Now you asked how to get all the info from the first table into the second. Use a query; drag both tables into it, (see the relationship again?), and draw down the fields you want. You'll see all fields without having to store them more than is necessary (i.e., once).
Make sense? If not, post back and we'll try again.
