If you are doing a DSN connect, there is no way to specify two different subsystems. If you are doing a CAF connect, DB2 itself does not allow multi-threading, so you are limited to attaching to a SINGLE SUBSYSTEM at one time. The only alternative is to download one table to a file and compare it against a live table on another system.
From IBM link: http://publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=%2Fcom.ibm. db2 .doc.apsg%2Frxspwrt.htm Writing a REXX stored procedure
