Can Race Tag change a stat value?

[Kaput]

I have the last vesion of army builder (3.5c) and I'm trying to begin the Data File for Age of Sigmar. I need help with the validation of a race.

In the game some units can be from a big alliance or can be from a allegiance. The only difference is that in the allegiance change the battlefield roll in some units.

I am trying to do that validation by the race tag, so the user choose the alliance or the allegiance both as a race. I decide to assume the battlefield roll as a stat value. So, I need that after choosing a race the battlefield roll change. How can I do that?

 

[Kaput]

I already had progress. I added on unit prelink button the next script:

~ Si se elige sólo Order Draconis se agrega Battleline como Rol en Batalla
if (tagis[roster.orderdraco] <> 0) then
perform assign[TipoUnidad.Bl]
perform assign[compgroup.tgLineab1K]
endif

It solves part of the problem, but can the stat be changed before the selection?