The ability to filter components for 64-bit systems appeared first in
InstallShield 11, thou it had a bug where you could specify that
component should install on 64-bit systems ONLY, but you couldn't
specify to install component on 32-bit systems only, which caused
64-bit components to be overwritten by their 32-bit siblings.
Fortunately that bug was fixed in InstallShield 11.5.
The way you filter components is thru the Platform Suites in component
properties.
Good Luck,
RUS