conditional value selection for restricted parameters

HI,

I want to set condition between two restricted parameters for selection of value to explain sub category of part,

for example:

1st parameter "PART_TYPE" with a restricted value ( 'INHOUSE', 'BOUGHTOUT')

2nd parameter  "CLASS" whith a value ("BED","BRACKET","HOUSING","BEARING","ORING","LM")

here I need another restriction on a value of 2nd parameter "CLASS" as follow

if  "PART_TYPE" = INHOUSE

then permitted value of "CLASS" should be from bed, bracket & housing

if  "PART_TYPE" = BOUGHTOUT

then permitted value of "CLASS" should be from bearing, oring & lm

awaiting for valuable suggestions from all members

with kind regards

DILIP VYAS