Thank you for all your information and tips.
Right now i just created on every toon with buffs 5 macros (one for every group member).
So i have to press 5 keys, to buff everyone with the group buffs (arcane intelligence, mark of the wild, blessing)

The suggested addons don't violate the WOW Classic TOS (Smartbuff and buffomat)?
It seems to me, there is a lot of automation going on there.