Your drawing can access data from any of the models referenced in the drawing.
Are you talking about the data entered in a format as a variable? This probably becomes specific to the active model in the drawing. If the variable does not exist, it is requested and that entry should propagate throughout all the sheets. There are also internal parameters that are Creo specific that can also be accessed.
Remember that parameters are the actual data in Creo files where relations are a means to assign and control parameters. You can create parameters without creating relations.
You can also use template drawings that already have the parameter created so that it i s always used when you start the drawing with that particular template. Again, this parameter shhould be accessible regardless of the active sheet.