Struggling with hotspot walled garden - hotspot only for specific sites

I have a fair amount of experience with Mikrotik’s hotspot service - but I have an unusual requirement that I’m struggling to make work.

I have a list of IP addresses for a special service, lets say 1.1.1.1, 2.2.2.2.

I’d like to use the hotspot to control access only to these special service IPs. I’d like all other traffic that is not destined to the special service IPs to bypass the hotspot completely with as little performance impact as possible.

I thought I could do this using ! (not) rules in the walled garden IP list, but this doesn’t seem to work. The walled garden ip list is not sequential, so I can’t deny 1.1.1.1, deny 2.2.2.2 and then allow 0.0.0.0.

I thought I could do this using the pre-hotspot chain - but was struggling to come up with the right rules.

Any suggestions greatly appreciated!