It really depends on what you intend to do with the plants in their final use. Their natural habit is to form a bushy tree, naturally branching rather than growing tall. If left in a cluster in the pot they will tend to push each other apart quite a bit and could become quite tangled in the middle. This may be okay in a large pot with plenty of room to spread; in a house you would get lots of flowers and benefit from the fragrance. So is a mature product which is wider than tall or taller than wide what you would prefer?
If the latter then it is probably fine to tease the plants apart into two groups of three or three groups of two or singles and re-pot. The smaller the groups the more you stand the risk of losing one due to excessive root damage. You might even have plants to give away...