Yes, you can; almost all the makes of Code 332 track can be freely intermixed (LGB, Piko, Aristo, Trainline45, Thiel, Heyn, USAT, AMS and others). I think Playmo's reply above refers to the fact that the track geometry can be different between brands (ie: curves may not be the same radius, points may be different lengths and so on), but that doesn't stop them all be inter-connectable.
Oh, and welcome to GSC!
Jon.
EDIT: PS: what you WILL find is that even while most makes will happily fit together, there may be some visual differences - sleeper shape, colour and spacing (for example, LGB sleepers are quite rounded compared with Piko ones that are very square-edged, Aristo sleepers are black rather than brown, and so on), and the colour of the brass used can also vary - Aristo rail is more of a yellow-golden colour and tends to stay that way, most others are more "brassy" looking and tarnish faster when used outside.