Hmmmm tricky......

A transistor is a bipolar device and using a multimeter isn't going to give an easily and reliable method of determining the collector and emitter.

The emitter region of the semiconductor is usually more heavily doped than the collector region, so using resistance measuring isn't going to show up the difference.

What you would need to do is build a simple two resistor circuit to give a bias current to the base and then measure the current flow in the emitter / collector. the one with the highest gain will be the collector.

Obviously for NPN and PNP devices you will have to reverse the voltage polarity.

John.