Well, wouldn't do it with one command. But this should work.

# this is the original string
$string=""; 
# then split on first ':'
($begin,$end)=split (/:/,$string,2); 
# remember every () separately
# this assumes that between () there are no more (), eg not (27(b))
while ($end=~m/\((.+?)\)/g) { 
  push (@result,$1); 
}
# add first
unshift (@result,$b);
# if wanted to remove () from first
# check if need to escape
$result[0]=~s/[()]/;
[download]

Update: fix typo.