Help with Deleting specific measures (its not what you think)

Hey guys and girls,
First post here and I'm relatively new to the world of Musecore.

I am trying to delete specific bars from a 3 part score I'm trying to create.
When-ever I delete the required measures from the specific instrument it also deletes the measures from the other 2 instruments.

Basically I only want 5 measures of a "Sample Bass Line" at the beginning of my score then do not want the bass measures to be present for the remainder of the score.

I hope this makes sense and someone can help me! :)

Cheers, Simon