Grouping

Grouping is a word not commonly used in isolation with regard to music notation, but it is a generic term I use for the rules which govern the grouping of consecutive quavers and which also apply to the use of ties.
The rules govern the beaming together of consecutive notes each of note length quaver or less.
The normal rule is that a set of notes which are all quavers or shorter should be grouped in whole beats, and each beat separated.
The following exceptions apply providing that all the notes involved are half the length of the beat (e.g. if the beat is crotchets all the notes are quavers, or if the beat is quavers all the notes are semiquavers):
- When there are four beats in a bar, the first two beats and the last two beats should be grouped, as in this example:
- When there are three beats in a bar, the whole bar should be one group:
  The first two beats or the last two beats should be grouped together.
- When the time signature is two beats in a bar, the whole bar should be one group: unless there is three or more notes in a beat, in which case, each beat should be separate.
Ties are needed when going between two beats which would not be grouped according to the rules above.
The rules above are not absolute, they can be broken for the sake of readability, or printability.