Public Sector Accounting - Revenue equivalent to Cash

Hello,

I work in a Public Sector Project where Grants and AR are implemented along with other modules.

We generate invoices in Grants, and transfer them to AR.

Invoices get accounted in AR as -> Dr Receivables Cr Unearned Revenue

We generate Revenue in Grants and for revenue, do the accounting in Grants only as Dr Unearned Rev Cr Revenue

Cash is received in Receivable.

Being a public sector, our client have a requirement that Revenue should always be equal to Cash.

Is it possible to achieve in AR?

Any ideas on achieving this would be welcome.