How do I make a partition an installer?

I do not have access to a USB stick right now, I want to install macOS Ventura on an external drive, so I partitioned that drive into two, one 20 GB partition for the installer, and another for the macOS installation.

Anyways, I fetched an installer from OpenCore, and as I prepared to start flashing it, I noticed OpenCore would only recognize the entire drive as a device to flash on, not individual partitions on it. I would like it to not do that and instead flash an installer on an individual partition.

I doubt this is not not possible because I installed macOS Mojave only a month ago with this exact technique, albeit that was a "normal" installation, not an OpenCore one.

submitted by /u/NSRedditShitposter
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