Here is an example of detecting mqtt devices, using mqtt wildcards and context storage. This is a simplified example. You could also use announce topics to create the context array.
Hope it helps you.
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\"#00FF00\" : \"#FF0000\")}]\t)^(name)[]","tot":"jsonata"},{"t":"set","p":"payload","pt":"msg","to":"tasmota","tot":"flow"}],"action":"","property":"","from":"","to":"","reg":false,"x":420,"y":3240,"wires":[["f93c17b321065488"]]},{"id":"f93c17b321065488","type":"ui_template","z":"da8a6ef0b3c9a5c8","group":"2d4fe667.28f8ba","name":"","order":18,"width":0,"height":0,"format":"<script>\nthis.scope.action = function(obj) { return obj; }\n</script>\n\n\n<md-list>\n <md-list-item ng-repeat=\"device in msg.payload\">\n <md-button class=\"md-ink-ripple\" \n style=\"color: {{device.color}}\"\n ng-click=\"send({payload:action({name: device.name, state: device.state})})\" \n >{{device.name}} -- {{device.state}}</md-button>\n </md-list-item>\n</md-list>","storeOutMessages":false,"fwdInMessages":false,"resendOnRefresh":true,"templateScope":"local","className":"","x":580,"y":3260,"wires":[["7a453ae2374c5358"]]},{"id":"7a453ae2374c5358","type":"change","z":"da8a6ef0b3c9a5c8","name":"","rules":[{"t":"set","p":"topic","pt":"msg","to":"$join($split($$.payload.name, \"/\")[[0..2]], \"/\") & \"/command\"\t","tot":"jsonata"},{"t":"set","p":"payload","pt":"msg","to":"$$.payload.state = 1 ? 0 : 1","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":760,"y":3260,"wires":[["c7694ee5f1ba16fe"]]},{"id":"c7694ee5f1ba16fe","type":"mqtt out","z":"da8a6ef0b3c9a5c8","name":"","topic":"","qos":"","retain":"","respTopic":"","contentType":"","userProps":"","correl":"","expiry":"","broker":"e8ba3ef5.22f4a8","x":950,"y":3280,"wires":[]},{"id":"e8ba3ef5.22f4a8","type":"mqtt-broker","name":"testb","broker":"192.168.1.25","port":"1883","clientid":"node-red-test","autoConnect":true,"usetls":false,"compatmode":false,"protocolVersion":"4","keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthRetain":"false","birthPayload":"","birthMsg":{},"closeTopic":"","closeQos":"0","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"userProps":"","sessionExpiry":""},{"id":"2d4fe667.28f8ba","type":"ui_group","name":"demo","tab":"1caa8458.b17814","order":2,"disp":true,"width":"12","collapse":false},{"id":"1caa8458.b17814","type":"ui_tab","name":"Demo","icon":"dashboard","order":1,"disabled":false,"hidden":false}]
To add devices add more inject pairs with different room names. You will have to adjust flow for your device command and status topics.
