I'd like to be sure it's working before trying it out since we had a few failures involving heroic id.
Is it possible to do this :
Wednesday : Raid A (main) kill the first 6 bosses with 4 heroic bosses.
Tuesday : Raid B (alts) kill the first 6 bosses in normal
Friday : Some players from raid B join raid A and do primordius + qon heroic
in your case, you will be able to form a raid of mixed plays Group A and B for EITHER normal or HC kills.
what you can NOT do.
Mix HC 10/25 (as in, do boss 1 25HC, boss 2 10 man HC - boss 3 25 man HC) even if all the same people - it will NOT allow you to do the second boss 10m HC.
MIX HC lockout of the same size.
group A kill boss 1 HC. group B kill boss 1 HC.
you can NOT mix A+B to make a group C killing second boss HC. (They can mix and kill the rest NORMAL)
NOTE: to get an HC lockout you do NOT need to kill the boss, only TRY the boss HC. (exception to this is if you TRY the first boss of an instance HC, and then reset the instance - you have no lockout.) example: kill first boss normal, have 1 try on second boss HC, call the raid. it is as if you have a lockout of killing the Fist boss HC.