Exemption in different levels

hello Experts,

The requirement is that my client wants to offer exemptions according to level basis,

for example telephone allowance which they pay everymonth basing on levels

Telephone L1-L3 2000

L4 750

L5 500

for level 1 to level 3 exemption upto 2000

for level 4 exemption 750

for level 5 exemption 500,

can somebody please suggest,

thanks

vj