In RUI,when building the ACRs we had 'IN' operator,but in VBS an equivalent of that is not available

Summary:

In RUI, while building ACR, an "IN" operator option was available to be used as a logical condition for evaluation.
for eaxmple if we take Grade code..

....rowVar_Assignment.Grade ID  In  (A;B;C) . 

But I am not able to find any equivalent to IN operator in VBS when trying to put a condition for a business Rule.

Tried putting a custom function in advanced expression but, issue is, as part of VBS rule conditions what ever value we enter say A,B,C etc that gets converted to a system generated numeric string so cannot handle through a function.