Target multiple architectures at once

Hey guys, I have an app I want to publish for linux-x64 and linux-arm64.

I'm using the "RunTimeIdentifier" option in the .csproj file, I tried

linux-x64;linux-arm64

linux-x64;linux-arm64

but this didn't work. Can't really find an answer online, is this not possible?

Target multiple architectures at once - C#