You can do this if the paired or tripled drivers are all located within the same IC chip. The circuits on one chip are closely matched to gain and saturation characteristics.

Normally, if you were building a discrete type circuit, and you wanted to parallel driver transistors it is usually necessary to place low resistance resistors in the emitter legs of each individual transistor. This has the effect of causing the load to balance between each transistor. If not done then the transistor(s) with the highest h_FE and lowest V_CEsat will bear most of the load.

Michael Karas