Complex sentence: In the nineties, they connected with the German band The Notwist, in Weilheim, with whom they still have ties; their producer, Olaf Opal, is also working for The Notwist.
Split into simpler sentences: In the nineties, they connected with the German The Notwist/Weilheim musical scene with whom they still have their ties. In fact, their producer, Olaf Opal, is also working for The Notwist.