Sorry, I was reading this on a phone right after getting up and apparently got fairly confused. Ignore all that, and just read this post.
The idea is to have an IP address that ALL Hotspots respond to.
First make an IP address that's always up - either another physical interface, or a loopback interface (empty bridge). Then map your Hotspot name to that IP address. Then use that IP address and name for all three Hotspots (maybe adjust that final command below as it edits ALL Hotspot profiles, you may want to change the three relevant ones one by one manually).
/interface bridge
add name=loopback auto-mac=no mac-address=aa:bb:cc:dd:ee:ff
/ip address
add address=172.31.255.255/32 interface=bridge
/ip dns static
add name=hotspot.local address=172.31.255.255
/ip hotspot profile
set [find] hotspot-address=172.31.255.255 dns-name=hotspot.local
Now all users on all Hotspots can do status-y things and interact with the Hotspot servlets by going to 'hotspot.local' or 172.31.255.255.
I do this with Hotspots stacked on VLAN interfaces, and use the IP address/name of the physical interface for all VLAN Hotspot instances. Works a treat.