In the standard natal arrangement, one palace can contain at most two of the fourteen major stars. Some palaces contain one, and some contain none. Three prominent names on a screen do not necessarily mean three major stars share a palace.
Where the limit comes from
The major stars belong to two groups, organized around Zi Wei and Tian Fu. Within each group, stars occupy distinct positions. Combining the two arrangements therefore allows at most one star from each group at a position.
This also means that two-star combinations are not arbitrary. A plausible interpretation cannot make an impossible pair into an actual chart placement.
Prominent minor stars still count differently
Imagine a palace listing Wu Qu, Tian Fu, Wen Chang and Lu Cun. Only Wu Qu and Tian Fu belong to the fourteen major stars. The others can matter in interpretation without increasing that count.
Typography is not a universal classification system. Central labels such as Life Ruler and Body Ruler are separate fields, too.
Borrowed-star notes and timing overlays need similar care. They do not add another set of resident natal stars. Separate the original placements from annotations before discussing a combination. A claim of three resident major stars in one natal palace calls for checking the rules or labels, not ranking which star dominates.