That's all you should be hearing.
.....
if the ATC you tuned in to has different frequencies for approach, tower and ground etc. In the sim ATC at smaller airport often does not have that so you'll hear everybody at the same frequency. You can check the frequencies for any airport with AFCAD. If it has only got "traffic" all communication will be on the same frequency. With AFCAD you can easily create frequencies for all the other functions (arrival, departure, ground, clearance and so on).
By the way, if it's to busy you could also lower the amount of AI traffic in the settings/ATC menu.
Hope this helps.
AJ