Hi Jaffar,
There was a similar question at the following link:
If you double-click the component that you want to have a different bit rate (like Bit Sequence Generators) you can either change the name of the variable from “Bit rate” to another name and add it as a Global Parameter or you can change the mode from “Script” to “Normal” and declare the value manually.
Keep in mind that other components also need the bit rate information (like Optical Time Domain Visualizers), so I would suggest adding the second bit rate as a global parameter.
Regards