1. NEED TO GO THROUGH A FILTER.
dbgroup(@groupTitle=x1)[
    members[
        alumi[
            person(@pName=x2)]]]
:-
Person(Y1),ResearchGroup(Y2),employs(Y2,Y1),
name(Y1,x2),name(Y2,x1).

2. NEED TO GO THROUGH A FILTER.
dbgroup(@groupTitle=x1)[
    members[
        alumi[
            person(@pName=x2)]]]
:-
Person(Y1),ResearchGroup(Y2),headPerson(Y2,Y1),
name(Y1,x2),name(Y2,x1).