How to force anti aliasing on epsxe games

if your hardware meets the requirements you can play around with some of the shader effects that can be used with the OGL2 plugin. while you cant force it through your control panel with that plugin like you are asking, there are a few shader effects like the natural vision shader that can provide a "fake" anti-aliased look to the overall image.

Anti Aliasing does nothing for the OGL 2 plugin, but can be enabled globally for the OGL1/D3D plugins.