How to perform intermarket analysis with MS 7.03?

[robsch@xxxxxxxxxxxxxxx (Robert Schien)]

Hello,

I am new to MetaStock and want to test some trading ideas.
One of these systems uses an intermarket.
Classical example: interest rate spread between US bonds and 
Euro bonds determines currency prices.
I have all the historic data, but how can I use a security
(or composite security) as an indicator in the Systems Tester
area?
More generally, how can I access multiple securities
in the formulation of indicators or system testers?
Are there perhaps some undocumented reference or access
functions which allow this?

I have digged through the help, but found nothing :(

Thank you in advance.
Robert