How can I set the brightness for a Ring lights group using Alexa voice command(s)?

I have several Smart Lights groups, a Ring Bridge, and several Amazon Alexa/Echo devices in my house.I want to use an Alexa voice command (or commands if necessary) to adjust the brightness of all the smart lights in an entire group, all at once.Is this possible? If this requires using the If This Than That app, please give me all the steps I would need.If this requires another "helper" app, please give me the details.Thank you.