Future Date Accounting Entry Post Restriction

We controls Posting Date for FI module through OB52 and MM side MMPV & MMRV.

When we open the period for 1 month. Then any user can post accounting entry for current month any dated. But, our client requirement is that any user will not post any document in the future date.

Example : Today is 05.07.2014.           Period Open for June 2014 & July 2014. ( Period Open for 2 months)

So, Users can post the entry of any date in the month of June 2014 & only posted 01.07.2014 to 05.07.2014 in July 2014.

But, they will not able to post the document after the 05.07.2014. ( i.e. 06.07.2014 to 31.07.2014).

We want system will restrict any Posting Date should not be grater than Entry Date.

Please suggest. (We use SAP 6.0)

With regards,

Uttam Maity