Read about START-PROF pipe stress analysis software
To split the reducer into 2 parts, add additional node 3 and change the diameter of the intermediate pipe 4-3
Now add two reducers into nodes 3 and 4
To add the branch into the intermediate node, add two more nodes 5 and 6 with a distance of 1 mm from each other. And increase the length of the pipe 3-4 by 2 millimeters
Now add the branch pipe into the node 5. And insert stub-in, joint or custom tee into the node 5