custom data validation

Dear Forum user,

For the sake of maintaining a data list about petty cash expenses. I wanted to use data validation for cell B2, in such a way that it should allow data to be entered into it based on the value in the cell A1, precisely speaking it should only allow data (any data text or number) to be eneterd, if the cell A1 contains any one of the follwing value:

bills
payable
receivable




I was trying to restrict the values from being enetered into the cell B2 by applying the following formula in the custom data validation.


=if(a2="bills", true, false)

but the problem with this formula is it only checks for the value "bills" in cell A1 and i want a formula like multiple if criteria so that it checks for all three values mentioned above (bills, payable and receivable)


please help