How can i use my HTTP proxy as client on OpenWrt?

I have an HTTP proxy server on my local network which is (the proxy has a VPN). I want to use the HTTP proxy address on my OpenWRT as a client like Proxifier (windows software) that all my router clients will auto use the HTTP proxy. Is it possible? BTW, I can use the proxy by Firefox browser if I add the proxy from the FIrefox setting. I want the exact firefox same thing on OpenWRT then client doesn't have need to add the proxy manually. Thanks in advance.

haproxy might be what you need.

Can you tell me the process to setup to haproxy?