It sounds like what you want is a Manager function (if I'm understanding correctly).
Say you have a Manager composed of some text fields - say, a VerticalFieldManager which represents a column in a grid. Here's some pseudocode which shows approximately how to set a column to the greatest width of all contained fields. HTH.
Code:
protected void sublayout(int width, int height) {
int maxWidth = 0;
int yOffset = 0;
int fieldCount = getFieldCount();
for (int i = 0; i < fieldCount; i++) {
Field field = getField(i);
layoutChild(field, width, height);
setPositionChild(field, 0, yOffset);
yOffset += field.getHeight();
maxWidth = Math.max(maxWidth, field.getWidth();
}
setExtent(maxWidth, yOffset);
}