Many source instances maps to many target instances

Each combination of the source instance types source::sEntA, source::sEntB, and source::sEntB that evaluates the WHEN clause to TRUE will be mapped to many (i.e. more than one) instances in the target model
 
MAP; -- no map entity specification.
FROM (s_eA:source::sEntA, s_eB:source::sEntB, s_eC:source::sEntC)
WHEN (TRUE);
BEGIN_MAP
 LOCAL
  mapInstA : GENERIC; -- Holds a map instance
  mapInstB : GENERIC; -- Holds a map instance
  mapInstC : GENERIC; -- Holds a map instance
  mapInstD : GENERIC; -- Holds a map instance
 END_LOCAL;
 xpxCreateMapInstance(target::EntityA, mapInstA);
 xpxCreateMapInstance(target::EntityB, mapInstB);
 xpxCreateMapInstance(target::EntityC, mapInstC);
 xpxCreateMapInstance(target::EntityD, mapInstD);
 (* Attribute mapping *)
 . . .
END_MAP;