So, technically you could do this. However, you need to make sure that the awning size is exactly the same size as the awning room you are attaching.
For example, the ARB awnings come in 3 widths, 1250, 2000, and 2500 measured in cm, leaving the 2500 awning at about a 8ft 2” width. The ARB awnings are also the same roll out length, at 2500.
If your Smittybuilt is exactly 98” wide and the same in roll out length, it would work. All awning systems use a Keder rail for mounting-it’s from the RV industry. So attaching the awning rooms utilize the Keder rail.