Complex sentence: Unlike the caste systems brought forward to Nepal region since the Hindu invasion, social discrimination or caste system is not practised among the Limbu tradition and Limbu sub-groups, however there are numerous different clans and family-sects.
Split into simpler sentences: Unlike the caste system which was brought to the Nepal region after the Hindu invasion, a caste system is not practised among the Limbu people and Limbu sub-groups. However, there are numerous different clans and family-sects.