Using multiple emulators

[ArisButCool]

im having this problem where i set multiple cores for a system, but i can only choose one of them, even when i go to execute with, retroarch, but its still only one option, im not wanting to use emulators for certain games, i just want the option to choose beetween genesis gx plus and gensgx plus wide

[Lordmonkus]

Manage Emulators > Retroarch > Associated Platforms
Add a new emulator entry for Sega Genesis and select the core you want.
Right click a game, Launch With > Retroarch > and click the core you want to start with.