How to refresh 2 logins of same website in same browser simultaneously?

I am using 2 Ipads as cash registers in two different business locations. Both Ipads have Square Register APP installed, but under different login and password or accounts.

Square register allows me to keep track of the Ipad sales on my IMac at the home office, but it is not "live". The browser window has to be refreshed in order to get the latest sales volume for the minute.

Since I have two independent accounts with Square, I tried opening 2 tabs with the Square website in Safari or Firefox and logged in using two different accounts at Square. Guess what: its a NO GO. There is a conflict. Both tabs want to use just one Square account, but never two accounts at same time.

Does not work if you are using the same browser. It could probably work with two different browsers, but I prefer to keep it all in one.

Any ideas on how this can be achieved using just one browser?

BTW, Firefox has this nifty plugin which allows for autorefresh avery few minutes.

Thanks in advance