How to create new ldevs on a certain type of spindel

I'm dealing with the following:
I need 2TB of mapped storage by tomorrow, made out of 15 metas, each made out of 8 ldevs of 17GB; all ldevs should come from 300GB spindels.

I don't have enough of those 17GB ldevs available, but I do have enough 8.5GB ldevs I don't need anymore. When I check these ldevs, I can see the following:

Device : 2280
{
--------------------------------------------------------------
Disk DA Hyper Member Spare Disk
DA :IT Vol# Num Cap(MB) Num Status Status Grp# Cap(MB)
--------------------------------------------------------------
01A:C8 238 44 2908 2 RW N/A 7 286102
05A:C8 238 44 2908 4 RW N/A 7 286102
11A:C16 571 44 2908 1 RW N/A 7 286102
15A:C16 571 44 2908 3 RW N/A 7 286102
}



Device : 22A0
{
--------------------------------------------------------------
Disk DA Hyper Member Spare Disk
DA :IT Vol# Num Cap(MB) Num Status Status Grp# Cap(MB)
--------------------------------------------------------------
01A:C8 239 45 2908 1 RW N/A 0 286102
05A:C8 239 45 2908 3 RW N/A 0 286102
11A:C16 581 45 2908 4 RW N/A 0 286102
15A:C16 581 45 2908 2 RW N/A 0 286102
}


I know that the number "286102" is the number of kBytes, so these are the 300GB spindels I want. The number before this 300GB is the disk group number. So in this case I have an ldev in disk group 7 and one in disk group 0.

Another ldev looks like this:
Device : 22A1
{
--------------------------------------------------------------
Disk DA Hyper Member Spare Disk
DA :IT Vol# Num Cap(MB) Num Status Status Grp# Cap(MB)
--------------------------------------------------------------
02D:Ca 296 45 2908 2 RW N/A 7 139828
06D:Ca 248 45 2908 4 RW N/A 7 139828
12D:Ca 296 45 2908 3 RW N/A 7 139828
16D:Ca 296 45 2908 1 RW N/A 7 139828
}

So suddenly my disk group 7 contains 146GB spindels ?
And what about the next one ?

Device : 22A6
{
--------------------------------------------------------------
Disk DA Hyper Member Spare Disk
DA :IT Vol# Num Cap(MB) Num Status Status Grp# Cap(MB)
--------------------------------------------------------------
01C:Ca 249 45 2908 1 RW N/A 0 286102
05C:Ca 249 45 2908 3 RW N/A 7 139828
11C:Ca 248 45 2908 4 RW N/A 7 139828
15C:Ca 248 45 2908 2 RW N/A 7 139828
}

Huh ?
I know I created these ldevs myself, but when creating ldevs with a command file you need to specify the disk group number and you cannot mention 2 disk groups, so how did this happen ?

This is the syntax:
create dev
count=64
size=37184
emulation=FBA
config=RAID-5
disk_group=0;

I'm now wondering whether or not the " disk_group" in this command file is the same as the one mentioned in the (partial) "symdev show" output I just mentioned.

How can I be sure that new ldevs will be created on the same type of spindel ?

Any thoughts on this ??