Block, group what else ?

Hi Community member,

I draw  something looking as an "h", with 3 straitgh lines in ortho mode.

I want to be able to enlarge my drawing along the horizontal axis by :
                     or i extend the horizontal bar  to the right
                     or moving the righter vertical line to the right
                     either moving the great vertical line to the left
AND all this lines must stay connected, how to solve this trick ?

I will stay able to extend the vertical lines as needed.

(Why such a drawing ? :  a clue : it's related to a cutting line)

Thanks in advance.