Based on load balancer selection, modify http-request

Help!
1

Hello,

I am attempting to execute a staged roll out of a new backend using weighted load balancing.
sample backend configuration:

mode http
reqidel ^Host:
reqadd Host:\
server api :80 weight 99

#only execute if moa is selected
http-request set-path /mobile-orchestration%[path]
http-request set-query %[query]&apikey=somekey

server moa :443 weight 1 check ssl verify none

The above configuration obviously does not work as desired. the http-request commands will be executed regardless of the server selected.

moa server requires the addition of a path prefix, api server must not have this. How can I modify this configuration such that the changes described by the http-request commands are only executed when the moa server is selected by the load balancer?

Thanks