i have cpanel server ( whm ) and 10 active user

i created a config file : custom.conf
Can I define an IfModule for a specific user in this file?

for example

cat /etc/apache2/conf.d/userdata/custom.conf

<IfModule MyApp $USER OR $Directory >
RewriteEngine On
</IfModule>

If I put it normally, it will run for all users. But I want to be active for a specific user or users.

thankyou