Depending on the venue, the number of people making up a group can vary from a minimum of 7 to 10 and a maximum of 20 to 30. Group visits are subject to certain conditions: specific times and days, advance bookings and, depending on the galleries or the type of exhibition, there is a limit to the number of people accepted.
If the range of scheduled guided tours for groups does not appeal to you, then you do have other alternatives.
A group composed of people of a similar profile or who are all interested in the same subject can visit a museum or a monument independently: in order to do this, you must have at least 7 people in your group, book the service of an approved guide who has prior knowledge of your requirements and book with the relevant department in plenty of time. Visits for school children accompanied by their teacher are also subject to certain conditions.