Sharing data between rule-sets

I have two rulesets in a common function. I want to pass a variable from one to the other. Onhttp://help.sap.com/saphelp_nw70ehp1/helpdata/en/32/6aba9c49fd41a5a14f710e121220f1/content.htmhttp://help.sap.com/saphelp_nw70ehp1/helpdata/en/32/6aba9c49fd41a5a14f710e121220f1/content.htm I read

Application [Access Level] - Objects can be accessed by all other objects under the particular application.

I assumed the this meant a value set in one ruleset would be visible in another providing I see the access level to application. However this is not true. Can someone explain to me:

1. how to pass data between rule sets
2. what the point of the access levels are. I have read the help on this topic but the evidence indicates I am not understanding what the documention is saying.

Thanks

Cliff