Shelly groups with alexa

Hi all, I have three Shelly 2.5 controlling 3 roller shutter. Is there a way to control them at the same time giving also a percentage, ie Alexa open home at 43%? Using Alexa groups only allows to say open/close, while I'm unable to make Alexa sees groups created on Shelly app...

Thanks!

Really, no one? 😞