Multiple partners/projects choice on events?

The current Dolibarr version 8.02 offers the possibility to link the calendar appointment with a company (partner) via a field. But, in the next selection field “Linked contact” only contacts that belong to this company can be selected. Conversely, if no company is selected, you can enter all existing contacts, but the appointment will not be registered with the selected persons and yu cannot see this way on a contact card when and where there were an common appointment with the person.

In real business life, e.g. at events/conferences or e.g. joint ventures, it is often the case that appointments with contacts from several companies. This case need to enter not only one but several companies (partners) and their contacts for a calendar appointment. - It there a way to configure the event firm this way?

One solution might be to offer a multiselection in the field “Linked companies”. But how can this be set up?

PS By the way, the same question also applies to projects: A event can also cover several projects and not just one.

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