How can I use a different browser for a specific app rather than the default?

I'm running 10.12.6 and using Firefox as the default browser. I would like to open just 1 or 2 apps on the Safari browser instead. So those apps would default to Safari when I click on links in their emails. For various reasons I am no wanting to switch default browsers in total or update the computer. IS what I'm asking not possible, or if it is, how do I set for two default browsers?