The point is to establish that the visitors from India really have no intention, and perhaps even no interest in, overstaying the duration of their visa, and have every intention of, and a desire and need to, return to India on the planned date. and also that you as their host really have no intention and even no interest in their staying on with you beyond the planned date, and have every intention of getting them back to their responsibilities in India.
They must show, and you must show, that this a temporary thing, a mere visit, and that after that life will go back to normal, with you living in Switzerland as you do now, and their returning to their usual life in India.
You can document your side by demonstrating, with all the necessary papers, that you getting along fine in your every-day life without these relatives by your side, that you are employed, very busy, established in connections with your friends, clubs, societies, neighbours, language courses, further studies, etc., here, and that during their visit you will be making a special effort to take some time off from these activities, but only because you know it cannot be and need not be sustained, since they will return to India after a short visit.
They can document their side by demonstrating that their whole life takes place in India, and that a whole host of responsibilities, duties, connections, their income, their bank accounts, their home, all their friends and relatives, and their social and community life takes place there . They are only briefly taking a short trip away from that, and will then, very naturally, be returning to take up their normal place in their life, neighbourhood and social and business circles, in India.
If in fact, you or any of the visitors have a dream of using the time to look around and see whether they could possibly ever come over to work or study or live with you in Switzerland, then you have to be very careful to keep that notion completely separate from their visa application.
Just focus on this holiday trip. After all, any sensible person who can afford to do so, should always first go on a holiday to a far-off country, to see if they think they'd like it there, before they would even contemplate leaving everything at home behind, and immigrating. Therefore, keep any hope of living in Switzerland (if they or you have such for them) completely in the realm of "dream" or "hope" and for now, and for this application, and also because it is reality-based (residence permits not easy to get for non-EU people anyway), and just stay very focussed on fact that this is just a holiday.