I need a reasponsibility which can enter/approve adjustment but not allowed to maintain Transactions

based on requirements that an individual user should not be able to create /maintain Transactions, but that user could be a manager and needs to approve adjustments.

I tried to execlude the function: Invoice Enter, after execlusion, that responsibility can't enter invoice but I found it can't approve adjustment also.

how can I execlude the function : Invoice enter, but keep the Adjustment Approval function?

thanks

Jimmy