How to make udev set constant event{N_i} for each i-th phys. device?

[Kārlis Repsons]

Hello!

I have multiseat system and one unsolved problem is making my keyboard and 
mouses always receive same event numbers!

1. How to do it by USB/ps2 inputs?\
2. How to do it by some device unique identifier?

cat /proc/bus/input/devices

I: Bus=0011 Vendor=0001 Product=0001 Version=ab41
N: Name="AT Translated Set 2 keyboard"
P: Phys=isa0060/serio0/input0
S: Sysfs=/class/input/input2
U: Uniq=
H: Handlers=kbd event2
B: EV=120013
B: KEY=402000000 3803078f800d001 feffffdfffefffff fffffffffffffffe
B: MSC=10
B: LED=7

I: Bus=0003 Vendor=046d Product=c315 Version=0110
N: Name="Logitech Logitech USB Keyboard"
P: Phys=usb-0000:00:1d.1-1/input0
S: Sysfs=/class/input/input19
U: Uniq=
H: Handlers=kbd event4
B: EV=120013
B: KEY=1000000000007 ff800000000007ff febeffdfffefffff fffffffffffffffe
B: MSC=10
B: LED=1f

I: Bus=0003 Vendor=046d Product=c050 Version=0110
N: Name="Logitech USB-PS/2 Optical Mouse"
P: Phys=usb-0000:00:1d.1-2/input0
S: Sysfs=/class/input/input20
U: Uniq=
H: Handlers=mouse0 event5
B: EV=17
B: KEY=ff0000 0 0 0 0
B: REL=143
B: MSC=10

I: Bus=0003 Vendor=046d Product=c018 Version=0111
N: Name="Logitech USB Optical Mouse"
P: Phys=usb-0000:00:1d.2-2/input0
S: Sysfs=/class/input/input21
U: Uniq=
H: Handlers=mouse1 event6
B: EV=17
B: KEY=70000 0 0 0 0
B: REL=103
B: MSC=10

I am not sure about how to identify each device... Is it possible?
Some advice appreciated...

K.