How to set up proxyremonte attribute in config files of sites in httpd?

[al.phonso]

Hello, i'm a hard working admin in a school.
a great problem to secure the internet connection for the pupils.
My way until today: for every computer room in our school were different sites with a free port (9303, 9302, 9301), so i can turn on and off.
There is also avery good free filtering software DANSGUARDIAN running on port 8080 with proxy an squid. But the ports of the three sites are not filtered by dansguardian.
So can anyone tell my exactly how to set up manualy the proxyremote attribut in the config files, because there is no way to set it up in serveradmin GUI.
Here is my file:
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## Default Virtual Host Configuration

<VirtualHost *:25303>
ServerName s303
ServerAdmin admin@example.com
DocumentRoot "/Library/WebServer/Documents"
DirectoryIndex "index.html" "index.php"
CustomLog "/var/log/httpd/access_log" "%{PC-Remote-Addr}i %l %u %t \"%r\" %>s %b"
ErrorLog "/var/log/httpd/error_log"
ErrorDocument 404 /error.html
<IfModule mod_ssl.c>
SSLEngine Off
SSLLog "/var/log/httpd/ssl_engine_log"
SSLCertificateFile "/etc/certificates/Default.crt"
SSLCertificateKeyFile "/etc/certificates/Default.key"
SSLCipherSuite "ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:+LOW:!SSLv2:+EXP:+eNULL"
</IfModule>
<IfModule mod_dav.c>
DAVLockDB "/var/run/davlocks/.davlock100"
DAVMinTimeout 600
</IfModule>
<Directory "/Library/WebServer/Documents">
Options All -Indexes -ExecCGI -Includes +MultiViews
AllowOverride None
<IfModule mod_dav.c>
DAV On
</IfModule>
</Directory>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_METHOD} ^TRACE
RewriteRule .* - [F]
</IfModule>
<IfModule mod_alias.c>
</IfModule>
LogLevel warn
</VirtualHost>
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Many thanks for all your help.