Thank you for the welcome to AAC!

How would that DPDT relay get wired? Something like the revision I've done below?

View attachment 272818

I’m in the middle of the same thing except I have two e stops and two alarms and I need either e stop to kill the pumps and sound both alarms

is it the same thing but another push button wired in series. And another alarm wired in series

Mod: link to old thread
https://forum.allaboutcircuits.com/...tton-shut-down-pool-pumps.188366/post-1752133

 

OK, what I suggest is using a relay with more contacts. In fact, for a scheme as demanding as an emergency shut-off, going to the expense of getting an actual industrial quality relay that will be happy to stay energized for a year at a time. That same relay can have four or more normally open contacts to shut down the various pump motor starters, and a normally closed contact to operate the alarm sound. AND, a holding contact so that it takes a different momentary switch to reset the circuit even after the big red button is pulled back out.
And the E-STOP switch should be similar to the industrial ones, maintained position, RED, sealed , and durable, so as to survive being slapped hard in an emergency.
In fact, to CYA, the whole E-STOP hardware should be industrial level durability. Then it will not need to be replaced or repaired for a whole lot of years.