[otrs] 'Close' ticket to customer when change queue

Hi We have a scenario, where we will use OTRS in a small company. We invoice every fortnight, and would like to use the mechanism of changing a queue from one the customer sees, to our 'Invoicing' queue as closure. Is this possible? There could be a scenario whereby a ticket moves queue 2 weeks ahead of it being invoiced (and then properly closed) and don't want the customer to think it's taken so long to resolve his issue! It would be ideal to trigger an email to them once we move the ticket from the support queue in this way. Thanks for your ideas Neil