Default browser. How to make two - one for some sites (by mask) and another for all the rest?

Question

Browsers

My favorite default browser, Chrome, is fine, but the firm's intranet sites only work fine in Firefox. Furthermore! It is impossible to even log in to many of Chrome. I think I need a redirect. Sites with the mask *my.firm.com/* and others open in Firefox, and all the rest in Chrome. At the last job there was the same picture, but IE was needed there. There are extensions for this (for example, the well-functioning IE Tab). But for Firefox, I did not find a similar extension.
What to do?

Answer 1

How many sites do you have there? Might just make a desktop shortcut with a command like:

firefox first.firm.com second.firm.com third.firm.com

and when you need to visit them - run it, and the rest of the time use chrome

Answer 2

OS what?
Plan 9? OpenVMX? haiku?