@Juan Andres currently not. You can save more simulations (for example multiple .tran simulations) in the same file and each graph displaying a different run (dataset), but it is currently not possible to load a .ac, a .tran and a .dc simulation from different files in the same schematic at the same time. A possible option is to open the same schematic in different xschem tabs, in this case each tab may load a different raw file.