Applies to: Red Range interfaces, RedNet PCIeNX, RedNet TNX

Mac
Yes - For this, you must be using a Mac using macOS Monterey or newer with RedNet Control 2.18.0 installed
To combine units, each device must be daisy-chained over Thunderbolt to the next unit's spare Thunderbolt port

Windows
No - Due to how Thunderbolt drivers work on Windows, driver aggregation is not supported. And RedNet Control will only work with one interface at a time, and the devices will be seen separately by your system rather than being aggregated.

The dual Thunderbolt ports on the Red Range are intended for adding other Thunderbolt peripherals to the chain (such as hard drives/displays or other 3rd party Thunderbolt interfaces) rather than adding additional Focusrite interfaces.