Masking at field level

Hello SDNers,

My concern is to allow view to several users by making MASKING AT FIELD LEVEL.

To make it clear:

Take one example of automobile giant in which certain views are needed :

a)Higher Managment View (Total Access to all the fields,say all 10 fields)

b)Sales View (which should be given access to say first 4 fields)

c)Finance VIew (which needs to have acess to some 7 fields)

As in the case mentioned i need Masking at Field level.

Share your views.

Solution will be rewarded.

Rgds,

Krutarth