situation:
4 mages usind DPS castsequence macro are blasting approaching mob
At the moment mob comes within Nova radius i want one of mages to snare it with Nova while the others continue blasting

In the same situation with one mage the macro will be quite simple
/stopcasting
/cast Frost nova

When i tried to write a macro for a group with RR Nova i came to a situation when whether i have to stopcasting all mages for only one to use Nova or i have to wait for mages to finish casting/channeling to Nowa.

1st situation (all stopcasting one drop Nova in RR)
/stopcasting
/castsequence Frost nova,,,

/stopcasting
/castsequence ,Frost nova,,

/stopcasting
/castsequence ,,Frost nova,

2nd situation (wait for the current spell to cast/channel completely then Nova in RR)

/castsequence Frost nova,,,

/castsequence ,Frost nova,,

/castsequence ,,Frost nova,

Both way i do not like.

I know, that keyclone feature RR can solve this, but I want to know if it can be done with the default macro language of WOW?
the reason is simple. I have more than one MB team and i dont want to setup keyclone RR keys each time i swich between teams