Examples:
SRM6+SRM4+SRM2
Note: In the video above, the SRM6 takes 2 volleys even though there are enough tubes for each missile system.
Spoiler
SRM6+SRM6+SRM6
Note: In the video above, the first group of SRM6 takes 1 volley, the next 2 and the last 3!

Spoiler
And finally, additional missile configurations:
SRM4+SRM4+SRM4 (10tubes)
Spoiler
LRM10+LRM5+SRM2 (17tubes)
Spoiler
I've submitted a support ticket in hopes it will be passed on to the devs.
Edited by StalaggtIKE, 16 July 2013 - 04:31 PM.