Welcome! 
I’m not sure I’m understanding your use of “>” in your post, but I think you can accomplish what you want to by using the techniques in the following community FAQ:
FAQ: Can I trigger an Echo Action without Speaking to It?
It’s pretty straightforward if you follow those steps. You will have your presence sensor trigger a virtual switch to go on or off, and that switch in turn activates a virtual sensor which you can use in an echo routine.
Also, I don’t know if it’s of any use to you, but Amazon has its own presence detection based on the Alexa app on your phone. So that’s yet another option. But it’s a “ when location changes” condition rather than a “while“ condition, so using it can be a little more complicated. I suspect for your particular use case the previous method will be more helpful to you, but I did just want to mention it.
