Apache2 - url router. How to direct only certain addresses to a certain folder?

Question

Apache HTTP Server

Hello!
The essence of the question is as follows:
1. There is a domain: http://backend.example.com- /var/www/backend
2. And also: https://example.com- /var/www/frontend
It is necessary that some addresses (for example, https://example.com/payment/success) are directed to the /var/www/backend folder
How to do this did not find.

Answer 1

As an option (as a crooked option):
a symlink in the /var/www/frontend directory to /var/www/backend ; mod_rewrite rule, from certain requests (/payment/success) to this symlink.