>>> SMARTS chemical reaction:
[*:1]Cl.[*:2]Br.[*:3]I>>c1c([*:1])cc([*:2])cc1([*:3])

>>> Reagents A file:
tests_A_Cl.smi

>>> Reagents B file:
tests_B_Br.smi

>>> Reagents C file:
tests_C_I.smi


>>> In case you need custom SMILES to test the feature:
CCl
CBr
CI

