Native Madarin speaker for 12 and 14 year old in person in Barcelona

We are looking for a native Manderin speaker from mainland China to speak Mandarin in our home with our two older children. Both have the basic knowledge and I am looking to for them both to be able to take the HSK1 exam in April 2023 and then keep advancing each year. I would like joint lessons for both children 1 or 2 x per week and I am looking for full immersion. If possible, there will be times such as the school holidays, where there would be opportunity for more lessons and if you could occasionally pick the 12 year up from school and bring her on the metro home it would be helpful, but always speaking Manderin. The lessons will take place in our apartment which is near the Metro "Villa Olimpic". Please contact me on here.
Please no Taiwanese (sorry) and no online lessons will be considered. Thank you,
Carol.