When you're listening to jazz how do you know what instrument you're hearing up front? I can tell a piano but others are trickier to discern.
I mean I don't now how this ever could really be a problem, but I imagine listening to them solo, so you are certain what instrument it is will help you develop an ear for larger environments
Jazz listeners will be rude about this because the distinction is second nature to them, but it's normal to get various brass and woodwind instruments confused if you aren't used to hearing them solo. Liner notes for albums will often tell you who is playing the solos - especially with big bands where there are lots of people on the same instrument.
The only way to learn to recognise it yourself is practice. You'll pick it up as you go along if you;re seriously interested in getting into jazz.