Two tools attached to one robot

Hello everyone, I am using multiple tools on one robot, tool 1 is fixed to the robot flange,
I need to connect tool 2 or tool 3 to tool1 , now I can connect tool 1 to the robot flange, how to connect tool 2 to tool 1 ?
Robot needs to change tools while working.
Please help with your answers, thank you.

You can read this topic.