There are both smartthings “routines” and Alexa “routines.” They work a little differently from each other, but either could solve this problem.
If you only need it to work with echo, don’t use an echo group, use an echo routine.
If you also wanted to use the same settings separately in SmartThings, you can use a SmartThings routine if you just want on/off , or I believe you can use a smartThings scene. Then you can have echo initiate that SmartThings routine.
You won’t need to use virtual switches unless you include something other than lighting devices, but if you do want to have a routine that also, say, locks the door or sets the alarm status, then you would use the virtual switch method.
So lots of different ways to do it , it just depends on the exact details.