Can you use the Assemble Joints or As-built Joint command to accomplish this task? Another command that may help is the Rigid Group command from the assembly drop down menu.
The screenshot is a bit too small side to see what is happening. Perhaps you could share a public link of the design?
Thanks,

yes, you're right, using a different combination of joints I can obtain what I need.
it's quite interesting because this kind of problems help me to to think about the design stimulating new solutions. thank you!