Passing PHP variables between products

[swissbob]

I have a php product hooked to global_start which adds in a banner add at the top of every page, and also does some basic geo-location and provides a country code. Obviously this requires a database access.

I want to be able to pass the same country code on to another product that shows another banner on the threads page (below the first post). This has to be hooked to the postbit_display_start to get it to work I think.

The question is - how do I store a global variable accessible in the second script please? I can't find anything about this through searching.