How can we create BU specific DFF at expense item line level?

User should only see the DFF at expense item line level based on the BU. They should see other BU DFF.
We are aware that the BU specific context is not available at expense line level, only available at expense header level. We also tried page composer adding EL expression to hide the DFF for specific BUs, but it is not working. We need specific EL expression to hide the DFF for specific BUs or any other way to achieve this requirement.