Ruling on reciting Al-Fatihah and Al-Salah Al-Ibrahimiyyah and concluding by reciting, 'Glorified be your Lord, the Lord of Honor and Power'

Q: We are a group of Muslim immigrants who work in France. We were gathered on Taqwa (fear/wariness of offending Allah) and following the Sunnah of the Prophet Muhammad (peace be upon him). We, by Allah's Will, managed to assign a hall to perform the Five Obligatory Daily Prayers. We chose an Imam, may Allah help him with this burden. In addition, we arranged to hold sessions on preaching and guidance from time to time. However, this group has started to gradually break up because (Part No. 2; Page No. 536) each one of us says after Taslim (salutation of peace ending the Prayer), “Subhan Allah [Glory be to Allah]" thirty-three times, "Al-hamdu lillah [All praise is due to Allah]" thirty-three times, and Allahu Akbar [Allah is the Greatest]" thirty-three times,” as an implementation of the Prophet's Hadith narrated by Abu Hurayrah, The poor people went to the Messenger of Allah (peace be upon him) and said, "The wealthy have obtained the highest ranks and lasting bliss. They perform Salah (Prayer) as we perform Salah, and they observe Sawm (Fasting) as we observe Sawm, but they have more wealth with which they perform Hajj and `Umrah, and give Sadaqah (voluntary charity)." He (peace be upon him) said, "Shall I tell you something that if you act upon it you will catch up with those who are ahead of you, and you will get ahead of those who are behind you? No one will be better than you, except those who do as you do. Say, "Subhan Allah (Glory be to Allah)," "Al-hamdu lillah (All praise is due to Allah)," and "Allahu Akbar (Allah is the Greatest)" thirty-three times after every Salah." Each one of us says the formula mentioned in the Hadith subvocally. After that we recite Al-Fatihah and Al-Salah Al-Ibrahimiyyah (the second part of Tashahhud) in congregation and end our gathering by reciting, "Glorified be your Lord, the Lord of Honor and Power! (He is free) from what they attribute unto Him! And peace be on the Messengers! And all the praise and thanks be to Allâh, Lord of the 'Alamîn (mankind, jinns and all that exists)." Some of the fellow brothers dissociated themselves from this practice. They said that it is a Bid`ah (innovation in religion), which we will bear its sin and the sin of those who follow us until the Day of Resurrection. Please give us a Fatwa regarding this matter. Is the recitation of Al-Fatihah, Al-Salah Al-Ibrahimiyyah, and the last three Ayahs of Surah Al-Saffat (180-182) in congregation good or is it a Bid`ah? Those fellow men do not perform Salah with us anymore until we abandon this practice. (Part No. 2; Page No. 537) There should be a Fatwa to end this disagreement. In case we are wrong, we will abstain from it and ask Allah to forgive us but in case we are right, we invoke Allah to guide those fellow brothers. We hope there will be no cause for disagreements, which destroy and shatter Muslims' unity.