Walk all ports on all nodes and group subinterface connections
    to only parent interface connection if it is possible

def resolveSharedConnections(root: LNode):
    """
    Walk all ports on all nodes and group subinterface connections
    to only parent interface connection if it is possible
    """
    for ch in root.children:
        resolveSharedConnections(ch)

    for ch in root.children:
        for p in ch.iterPorts():
            portTryReduce(root, p)