4 Separate 'Piano' bars at the beginning of a score. Then come the 4 voices and the subsequent 'piano' bars are linked to these? linked to the 4 voices

I sing with a choir and find using Musescore very useful when learning a new son. However creating the score can be difficult as I am not 'musically minded' but I can mirror what is on a paper score. Muse score if great as I can repeat a part of a score any number of times.
The piano introduction on the piece is separate from the 4 voices and a subsequent piano:
Piano Treble - 4 bars

T1
T2
B1
B2
Piano Treble
Piano Bass

When I play the piece, everything plays at the same time. How can I split the first piano from the rest of the score? Help