Delete a row from a different subform

I have two subforms (SUB1 & SUB2) with a repeating row (Container) for each data item . A new "Container" row is added to each Subform via an Add row button. NOTE: When the button is pressed, both subforms receive an additional row:

SUB1._Container.addInstance();

SUB2._Container.addInstance();

Currently, the form is setup to auto-copy data from certain fields  in the Container row of SUB1 into the Container row of SUB 2, and all is working fine. What I'm looking for is...whenever I delete a row from SUB1 ( via _Container.removeInstance(this.parent.index); ), I'd like that the same "index" row to be deleted from SUB2. So if instance 3 is deleted from SUB1, I'd like instance 3 to be deleted from SUB2.

Any suggestions?

Thanks in advance.