This is the way that I do upgrades and create packages for my environment.
We first started off with the default rule for all the endpoints. Then, to upgrade those clients to a new version, I would upload the new installers, create a package/rule for export (for new machines) and then in the software deployment rules, create a new rule with the new group I created. I can now just add the users/computers to this group and they will get the upgrades. Once everyone is in that group, you can just change the default global rule to be the same rule as the one you created to do the upgrades, then delete that rule.
If you have computers that need different rules, the upgrade path is pretty much the same. Just move the users/computers into the new group and when you are done you can just delete the old group/rule they had.
This is good as you can put your test machines, then test users in there first before you just blanket everyone. Also, if you have certain machines with certain blades/rules, you will always be using groups anyway. We have the default rule and upgrade group for computer that do not use FDE, and a group/upgrade group for computers with FDE.
To make it easier, you can specify what group a brand new client goes in to in the Packages for Export tab in Deployment when you install CheckPoint Endpoint on a brand new computer.