This is what I make of what you want:
[{"id":"551987b32f6c9f7c","type":"inject","z":"437e4108076e5928","name":"Event happens","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"event","payloadType":"str","x":120,"y":580,"wires":[["5e9111fb135beb8f"]]},{"id":"5e9111fb135beb8f","type":"trigger","z":"437e4108076e5928","name":"Delay / check message is sent","op1":"","op2":"","op1type":"pay","op2type":"pay","duration":"3","extend":false,"overrideDelay":false,"units":"min","reset":"","bytopic":"all","topic":"topic","outputs":1,"x":360,"y":580,"wires":[["ab5b38cbb53dd04a"]]},{"id":"7b71d07e62d565f3","type":"change","z":"437e4108076e5928","name":"","rules":[{"t":"set","p":"reset","pt":"msg","to":"true","tot":"bool"}],"action":"","property":"","from":"","to":"","reg":false,"x":140,"y":630,"wires":[["5e9111fb135beb8f"]]},{"id":"63ec6a72c012ec86","type":"function","z":"437e4108076e5928","name":"Receiver","func":"\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":880,"y":580,"wires":[["7b71d07e62d565f3","a809de586ccd66fb"]]},{"id":"ad3ed249aba3686b","type":"comment","z":"437e4108076e5928","name":"Ack message received","info":"","x":920,"y":620,"wires":[]},{"id":"a809de586ccd66fb","type":"debug","z":"437e4108076e5928","name":"The rest of the flow.","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":1080,"y":580,"wires":[]},{"id":"6733d3d2f99af943","type":"comment","z":"437e4108076e5928","name":"Adjust the node below as needed","info":"","x":360,"y":540,"wires":[]},{"id":"ab5b38cbb53dd04a","type":"delay","z":"437e4108076e5928","name":"","pauseType":"delay","timeout":"5","timeoutUnits":"seconds","rate":"1","nbRateUnits":"1","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":false,"allowrate":false,"outputs":1,"x":640,"y":580,"wires":[["63ec6a72c012ec86"]]},{"id":"325dd8ceb86f897e","type":"comment","z":"437e4108076e5928","name":"Inherrent delays","info":"","x":660,"y":540,"wires":[]}]