Windows: equivalent of OS X’s Terminal “&”

Is there any way, under Windows 7, to emulate the behaviour of the & character in OS X's Terminal?
I'm trying to run multiple Wget instances simultaneously: I can do this without any problem of sort under OS X, because I have a Python script which builds a long string, in which each instance of Wget is &-separated. When I execute it with os.system() everything goes fine.
Under Windows, though, this doesn't work, and the instances are run in sequence. Which is not what I want.
I'm open to all suggestions: cmd.exe hacks, shell ports, more Python, anything, as long as new windows shell windows are created. Thanks in advance!

Edit: I've found out that files are in fact downloaded using this method, but under Windows, cmd.exe just ends abruptly the execution, and lets the user accept new commands. Is there any way to avoid this, and keep the console "hanging" until all Wget instances have finished downloading?

Edit 2: posting the code I'm using.

for track in album.tracks():
    tracknum = track["track_num"]
    tracktit = track["title"]
    URL = track["file"]["mp3-128"]
    filename = str(tracknum) + " - " + tracktit + ".mp3"

Now, under OS X, this code work wonderfully.

    execstr += 'bandcamp-support' +os.sep+ 'wget --tries=0 -O"{}" "{}" -q & '.format(filename,URL)
    os.system('bandcamp-support' +os.sep+ 'wget' execstr[:-3])

Under Windows, instead, this doesn't replicate the behaviour that I experience on OS X.

    os.system('start /B bandcamp-support' +os.sep+ 'wget --tries=0 -q -O"{}" "{}"'.format(filename,URL))