This has been asked recently:
http://forum.1cpublishing.eu/showthread.php?t=8525
As is posted there, the short answer is no - Unless you are willing to do a bit of messing around with the game files, i don't think it's possible. Though i'm sure an admin or modder would be able to give you idea of how hard it would be. (if it's possible at all)
I can see where you are coming from, but just think of being forced to play in normal mode as a test after all your training in slower speeds.
I also used to want to be able to adjust the speeds, but mostly because i enjoy the action and suspense of the slow motion - You can fire a round and still have to wait a while before it hits (and same goes with being shot at) so it adds a bit of panic and excitement to the already intense game.
However when you are playing with friends, and have less to manage yourself - It should be much easier to focus on just your own troops.
If you are desperate...I guess you could try upping the graphic details and remove some RAM to slow it down?
