Bracket Two Voices Together

I am writing an SATB score with SA on one staff and TB on the other. In the final bar on the TB staff I want to write 3 notes, all semibreves: A in the tenor (voice 1), D in first bass (voice 2) and low D in second bass (voice 3). In other scores that I have seen the two bass notes (D and low D) would be grouped together by a square bracket, but I can't find any way to do this in Musescore. Can anyone help?