Sayyed Mohammad Al-Musawi,
Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to religious questions. In the past, he has also spent significant time in India guiding the community.
If the time of congregational prayers does not allow you to perform Nafilah of Zohr or/ and Nafilah of Asr, then you can perform the Nafilah after the Jama'at prayers is over, with the Niyyah of Qadha.
You will then get the reward of Jama'at and the reward of performing the Nafilah.
If you have little time which will kot be enough to perform the whole eight Rak'ats of the Nafilah, you can perform few Rak'ats like 2 or 4 Rak'ats.