Restrict user report data based on flexfield segment value

Hi,

We are on R12.1.3 with only one Operating Unit.

We want to restrict report data based on users department which is maintained using second segment of accounting flexfeild. What is the best way to restrict data based on flexfield segments.

For ex:

We are segregating department data based on our second segment of general ledger flexfeild.

01-301-15000-00000-00000           -          301 - Construction Division

01-401-15000-00000-00000           -          401 - Lift Division

When a user of 301 division runs General Ledger (180 Char) char, report should not include any data for 401 segment.  I tried to implement value set security but this will  only work with a