SQL - How to create multiple if/case when statement that can return true to 1 or more condition

Here is my sample code i want to be processed:

Select 
cust = case 
when cust1<>cust2 then cust + cust1 ------> returns true
when cust1<>cust3 then cust + cust2 ------> returns true also
when cust1<>cust3 then cust + cust3 ------> false
else '' end
from tblCust