It won't be automatic, but what you may want to try creating hidden effective and expiration date columns for the entries.  Enter an effective and expiration dates for the items.

Then, add filtering to the copy of the F&L or XML module so that it only displays that items which fall between these effective/expiration dates.

Below is an example of the filtering we have for items.  We also include an "Active" true/false checkbox so that if it's checked as active, it's displayed.  Otherwise, it looks at the effective/expiration dates.

(([Active_UDT_Original] = 'True') OR ([Effective Date_udt_Ticks] <= [Ticks:Now] AND [Expiration Date_udt_Ticks] >= [Ticks:Now]))

Hope this helps.. -Jeff