Two options that I know of
1) Create a custom property in your sheet set manager that belongs to the sheet set (not the individual sheets). You can then add a field in your title block to this. You can also add all project specific information that will be displayed in your title block this way.
2) Create a drawing for your title block with all the project specific information in it and then xref this drawing into each layout.
I'm kind of partial to the first option myself because I can then reference that information elsewhere in the project.
Brian Hailey
http://www.cad-1.com
http://.www.AtYourDeskTraining.com