prevent adding same contacts in groups when doing a multiple selection of a group and some stuff in it
prevent adding same contacts in groups when doing a multiple selection of a group and some stuff in it

ArchipelProject/Archipel,ArchipelProject/Archipel,ruthger/Archipel,fr34k8/Archipel,ArchipelProject/Archipel,fr34k8/Archipel,rmoorman/Archipel,rmoorman/Archipel,ruthger/Archipel,rmoorman/Archipel,ArchipelProject/Archipel,rmoorman/Archipel,rmoorman/Archipel,ruthger/Archipel,CyrilPeponnet/Archipel,ruthger/Archipel,CyrilPeponnet/Archipel,fr34k8/Archipel,fr34k8/Archipel,CyrilPeponnet/Archipel,CyrilPeponnet/Archipel,CyrilPeponnet/Archipel,ruthger/Archipel,fr34k8/Archipel,ArchipelProject/Archipel