You could automate that using some scripting.
You can browse through the available updates using aptitude. Once you installed them, you can use the following command to get a definitive list of installed packages (with their respective version numbers):
Code:
apt-show-versions | sed -e 's:\/.*\(from\|uptodate\) :=:' | awk '{print $1}'
This can be used as command line input for apt-get/aptitude "install" command the other boxes.
On a debian system, I would just install all security upgrades without hesitating because debian guarantees there will never be any incompatibilities by not accepting newer versions as security updates but -- if necessary -- porting the patches back to the current stable distribution's version. But I'm not entirely sure Ubuntu follows the same safe policy