LG VX-8100

How can you specify if you want to be on a 3 way call or just 2 different calls, switching back and forth? If you call someone while already on a call, it first has that person as a separate call. Then, once you press send, it joins them, and you can't go back to one at a time. Similarly, when someone calls you while you're on a call, you CAN'T join the calls!

Am I missing something here?

Thanks.