I have built 7 identical tubes and placed them at the correct geometrical coordinates. Now I want to connect these tubes with rigid connections (or other types of connection, problem remains the same).

I looked for a 'CONNECT' function but could only find the CLOSE LOOP function. And I don't understand how it works.

This is what I do:

I have 6 tubes, tube 1 is nodes 5010-5060, tube 2 is nodes 5110-5160, tube 3 is nodes 5210-5260, etc
Each tube is at its correct absolute coordinates positioned in space.
I try to set up a new connection between for instance node 5020 (tube 1) and 5120 (tube 2).
I enter the node numbers 5020 and 5120 and click on CLOSE LOOP. I am now asked for new global coordinates for node 5110 (???), which I just don't understand. Entering or canceling now messes up my model.

What do I do wrong, or (better) how do I connect two existing nodes without changing their absolute coordinates?
I tried several other things like creating a new section and then changing node numbers but that messes up my model too.

I just can't believe this isn't possible, so what am I overlooking?

Any help strongly appreciated right now!