it's possible use RTMP variables on nginx environment?

Question

I want to know if it's possible use a rtmp url like this:

rtmp://server.com/live/user

and get variables inside like:

rtmp{
server{
application live{
if($name = 'user'){
   set $strmUrl "uqhiuwuywgbefbshd";
}

push ramp://other_server.com/live/$strmUrl;
}
}
}

I ask this because right now I'm trying to use that but return error when I try to restart nginx, I know I'm doing something wrong, but don't know where.

I know I can do something easy like just create new applications to use another values, but I want to have something dynamic so I ca use the same slag /live/

Any help or recommendation?