In a system, a first status of a first ESP engine (ESPE) executing at a first computing device is determined as newly active; a last published event block object identifier is determined as an identifier uniquely identifying a last event block object published to an out-messaging network device; a next event block object having an event block object identifier greater than the determined last published event block object identifier is selected from a first computer-readable medium; and the selected next event block object is published to the out-messaging network device. A first event block object is received from a second ESPE executing at a second computing device. A first status of the second ESPE is determined as standby by the second computing device. The received first event block object is stored by the second computing device in a second non-transitory computer-readable medium.