My try; slow, not very short, but interesting (uses one of my favorite modules):

use strict;
use Quantum::Superpositions qw(any);
my @r = (0..25);
sub c
{
   ($_[0]%3)==0;
}

##
sub S{my@Q=@_;@_=grep{c($_)}@Q;@Q=grep{any(@_)ne$_}@Q;@_}
##

print S(@r);
[download]

50 chars for the sub body, 36 for the use line.