How to automate the cash account derivation based on the transaction date on the ExternalTransaction

Summary:

Our issue is, currently we are using the attached workaround rule to derive the cash account on the external transaction.

in that rule, we have to update the between dates then only it will work.

we don't want to enter the dates manually; we want any formula/other way to automate the date derivation and based on that cash account should default on the external transaction.

let me know, if there is any way.

Content (required):

We need to derive the cash account based on the transaction date on the external transaction.

Example: 

 

If the transaction date is between 1 to 25 then cash account should be 1000