i need a posting period on transactions so that i can track transactions by period regardless of the date of a transaction. for example, i have an invoice dated 1/1/2015 & another invoice dated 3/4/2015, and i want them both to post in FEB 2015 (because what period both are charging for). then i want to select FEB 2015 from a dropdown on each transaction. i want calendar months as my choices, but others may want years or quarters.

& reports should be able to filter & aggregate data based on desired periods.