Bathroom Extractor with sensor

I have two bathroom extractors, one in the ensuite and the other in the master bathroom. Both extractors use the same ducting to extract out of the roof, and both are connected to the lights and run for 15 minutes once the light is switched off.

I was thinking of putting another inline fan closer to the roof outlet to give a higher extraction rate, my question is can I use something like the Fibaro Smart Implant on the two original fans, when they power up have something power up the third fan, when the fans go off so does the third??

I just have them linked to a normal relay as fibaro fgs223. As the extractor will report consumed watts, it’s easy to link it in scenes. I use one for example to be triggered when my dryer has fineshed or humidity has raised. It could be used for the opposite as well.

Thats a good idea, thanks!