One toolbar in MDI, all child reacts to it individually

What I want to do is to place a toolbar in the MDI form with buttons New, Edit, Delete, etc, and if a child form is shown and I clicked New on the toolbar it should open up a form which will add a record for that particular child form, what would be an elegant way to do this?

And I am wanting that upon loading a child form it can disable/enable/add/remove items in the toolbar.

TIA