How to delegate DNS zone?

[_gotd]

Current setup:

VPS with IP: 1.1.1.1 running Plesk (Linux)
A.com and B.com are both hosted on 1.1.1.1
Both websites are working fine at the moment.
ns1.B.com (which resolves to 1.1.1.1) is the name server for A.com & B.com at the registrar

I'd like to move A.com to another server 2.2.2.2 also running Plesk with DNS. I'd like to delegate the A.com zone at 1.1.1.1 to 2.2.2.2

What's the proper way to do this in Plesk without changing the name server (ns1.B.com) at the registrar?

Everything I have tried so far has failed.

Also worth mentioning that 2.2.2.2 has a zone for A.com. Everything on 2.2.2.2 for A.com is working.

I can do:
dig @2.2.2.2 A.com (and get A.com -> 2.2.2.2)