Add variable to a few layers one time

Is it possible add text variable to a few layers one time?

For example I need to add the same name variable to 300 text layers each separately.

1) I selected 50 text layers then "image > variables > define" and I added name for text variable. Then click OK. But only one of all layer (which I selected) have added variable. 
2) I added text variable to one text layer. When I duplicate this layer duplicated layer don't have any text variable.

Should be great, if will be Possibility to select a few text layers and give them a variable at the same time.