Use of multiple SmartThings hubs with Echo

Hello everyone,

I am finding myself going around in circles on this issue. So I am hoping if I describe the issue well enough someone might be able to direct me to a solution.

I have 1 Amazon Echo and 2 Echo Dots. I also have 2 SmartThings hubs, one in the house and another in a pole barn next to the house. I’d like to add another SmartThings hub to the works, this time in my outdoor observatory. But Echo will only allow me to connect one SmartThings hub. I’ve seen posts talking about setting up with different Amazon accounts (which I still am not clear on this procedure) and some posts saying to use Alexa Helper.

How should I go about setting up my HA with all my Echos and all my SmartThings hubs so that I can access all devices no matter which Echo I am near?