Limit a list box selection and then when selected, remove some items from another field

[tinkerz1]

Hi,

I am trying to write a list box expression to limit the items in the Line of business list box to one item 'ABC' and then when its selected select 'ABD' less products 'A'.

My example is below which I place in list box expression.

=if(LineOfBusiness = 'ABC',Select (LineOFBusiness='ABC' less Product 'A'),null())

Thanks

Tinkerz

[Anil_Babu_Samineni]

Please explain with raw data which can help us to think?