Join two lines to make one but without group?

"join A to B to make one line without using group"

Basically, you can’t.
By definition, a path consists of vectors joined by nodes. Each node sits between at most two vectors, so you cannot have a T intersection with three vectors meeting at a node.
What you can do is use the Node Editor to trim the vertical line where it meets the horizontal line. Then you group the two lines into a single unit that you can move around as needed.