graphviz: Create new node with this same label

You could define your nodes explicitly and set the label for them. Then each node has an unique id, but can have the same labels. Consider this example:

strict graph G {
    1 [label="A"];
    2 [label="B"];
    3 [label="B"];
    4 [label="A"];
    1 -- 2;
    2 -- 3;
    3 -- 4;
}

which will output (with dot):