Hard-coded way:
Trigger Expression IF(OR(s_1_back_price=s_2_back_price,s_1_back_price=s_3_back_price,s_1_back_price=s_4_back_prices_2_back_price=s_3_back_price,s_2_back_price=s_4_back_price,s_3_back_price=s_4_back_price), 1,0) is equal to 0
Right way:
1. Create a trigger variable
2. every round set it to 1 if
Any Other Selection's Back price is equal to back_price
3. Check it in betting trigger.