One data dir and two servers

Hello people,

I'd like to be able to run one of TWO independently installed server
instances on the same single data cluster. Actually, there are even
2 separate OS instances for that, though they are mostly identical and
they share the same harddisk. Server instances are also identical
versions.
I've tried to just create the cluster once and then point the 'second'
server instance to the existing cluster but it refused to start (with
no detailed complaint, just abnormal termination).
So, is this doable at all? Could someone give me a hint on any tricks
needed or whatever?
If it matters, I'm currently trying this on Windows.

P.S. please CC me, I'm not subscribed.

Thank you,
Nikolai ZHUBR