Closing charge accounts with outstanding encumbrances

We have an ongoing issue with closing of charge accounts/activity codes.

We use encumbrance accounting and can end date/disable activity codes in GL as and when the requirement arises.  The issue is that, at month end, any outstanding obligations associated with the accounts that have been closed cannot be swept into the next financial period.  We now have a large number of accounts we need to close and so it's not practical to re-open and close them every month to sweep the encumbrances into the next period.  Is there a way of closing activity codes that have outstanding encumbrances without here being a detrimental effect on the month/year end processing?