Is it possible to combine 2 or more businesses in one box?

I know what kind of client this is and his situation, three people have already eaten my ears with this task :)
Most likely, the client wants to combine two businesses into one box, because this business will have common employees, in particular, a contact center.
Sculpting two businesses into one box - in the long run, is a shitty idea. Imagine that you set up a second business in the same box, and suddenly the business turned out, shot and popped. Or an investor came and gave a lot of money. How will you share? How to manage finances, documents, events? After all, you will physically have other employees, other administrators (you need admin rights in the box, for settings).
After all, all integrations with telephony, sms, etc. are accessed only once in one box. You will not be able to connect two turbosms, two asterisks, two 1Ski to one OneBox. (And taking into account OneBox OS, we will not finish this feature).
I speak for myself: I now have three active businesses (including inactive ones - 10). For each, I created a separate cloud OneBox, as well as one "main OneBox", in which all businesses were just like projects with responsible people, I set tasks for them, made payments as investments (if I poured in) or dividends (if I took them out). Tasks from the main one were synchronized to the child ones and assigned to the heads of the companies.
In general, if a client wants to “try a second business”, then it’s better to have a minimal cloud box, make minimal integrations there, let employees go there, or synchronize tasks for the contact center.
It's easier, faster and cheaper in the long run.