In Dragon Age origins can you prevent a teammate from casting a sustained spell?

I have to choose some sustained spells just so i can keep a tree going to get the later spells, and it turns out that the party member "lets say wynne" now keeps casting her cleansing aura and burns the crap outta her mana, and another case is my warrior whoes a DW warrior keeps casting threaten when i swap off of him to cast other spells, is there any way i can prevent them from casting these?In Dragon Age origins can you prevent a teammate from casting a sustained spell?
go in to tactics menu defualt button is \ or / *always mix the 2 up*

and just change there skills to a dif one or none