The tbar device has an associated label (defaulting to the device name) which can be changed by the user by selecting the label and pressing the label button in the side menu. All nodes connected to a terminal device with the same label are taken as being connected together. The label of the terminal device is also used to name the node in netlist output.
This will not tie nodes between the main circuit and subcircuits, or between subcircuits, unless the terminal name is also defined in a .global line for SPICE. If not global, the scope is within the cell only. The .global line can be added as a spicetext label.