Several Handashakes in a sinlge file

[powermi]

Hi, i'm quite new on Hashcat, and reading from the wiki I saw that it's possible to use a dictionary attack over a single .hccapx with several handshakes. 
Do I need to first add every single handshake to the hccapx file? or could I just convert a .cap with all of the handshakes to the .hccapx file?
will hascath save the possible cracked password linked to each BSSID?

Thanks.