Can a staff style affect a group name?

I do not think so (but I could be wrong).

I would use multiple staff groups, one group for each region, letting the group name display as “all viols.” where needed (rather than letting a staff style display a staff name of “all viols.”) - in that way there is only need for a staff style that hides the staff name.

Dear Peter,

I have a similar problem.  I have string div., where sometimes violin 1 is divided into two parts and notated on two staves, and sometimes where they are just on one stave playing together.  Following the notational practice of the publishers Faber Music, when a string part is divisi on two staves, I want to include (as a group name) the indication Vn. 1 div. (instead of the usual group name Vn. 1), *without* individual staff names showing. 

I have understood that essentially I do not need staff names at all for the first violins for the entire piece, because when they are on one staff, the group name appears anyway, and when they are divisi, I do not want any staff names to show anyway.  This is easy to achieve.  

What I can't achieve (in a straightforward or elegant way) is having the two different group names, the one for the divisi on two staves situation ("Vn. 1 div."), and the normal one ("Vn. 1") for the single staff situation. 

I can think of two makeshift solutions:

1. add two entirely new staves to the whole score, for special use in the divisi situation.  This involves annoying copy and pasting and hiding of staves etc. 

2.  In the divisi situation, using the normal group name and creating text or an articulation with the word "div.", attached to the first bar of the system, which I can manually position below the group name, to appear as part of the group name.  This seems unreliable, as I would be afraid of the text/articulation unexpectedly moving when changes occur in the layout of the score.  

Are there any other ways of achieving the result I desire that are less inconvenient, or liable to result in unexpected problems if things get inadvertently moved around?

Thanks! 

I've worked it out!  In the Group Attributes dialogue, you can select the measure to which you want that grouping to apply.  I think that's problem solved now.