+----------------------------+----------------------------+-----------------------------+
| ?s                         | ?p                         | ?o                          |
| <test/Issue-opt-group/x.s> | <test/Issue-opt-group/x.p> | <test/Issue-opt-group/x.o1> |
| <test/Issue-opt-group/x.s> | <test/Issue-opt-group/x.p> | <test/Issue-opt-group/x.o2> |
| <test/Issue-opt-group/x.s> | <test/Issue-opt-group/x.p> | <test/Issue-opt-group/x.o3> |
+----------------------------+----------------------------+-----------------------------+