In Internet Explorer you can go into Internet Options and manually type in multiple Home pages to open whenever the browser opened. This feature still exists in Microsoft Edge for Windows 10 and configuring it is just a bit different.
To do this:
In Microsoft Edge, tap or click the ellipsis at the top right to display the dropdown menu, then navigate down to Settings.
Locate the Open With area and select the option for A specific page or pages option.
Tap or click the dropdown menu and choose Custom.
Add websites you want to store as "home pages" in the Enter a web address box provided and then tap or click the Plus (+) sign.
As you can see from my configuration, I chose MSN and Bing to open automatically in separate tabs every time Microsoft Edge is launched.