Something like this?
<%if FatherID eq '1000'%><%include page1.html%>
<%elsif FatherID eq '2000'%><%include page2.html%>
<%elsif FatherID eq '3000'%><%include page3.html%><%endif%>
<%if FatherID eq '1000'%><%include page1.html%>
<%elsif FatherID eq '2000'%><%include page2.html%>
<%elsif FatherID eq '3000'%><%include page3.html%><%endif%>