Why don't I have sharing on my calendar, with a shared account?

[AC Question]

not sharing on calender, with a shared account

We have one google account for all our work phones so that staff can use the playstore, but we are having a problem that people are getting calender invites to there work email address (which isn't google linked) and when they save it, it gets put on the splanner for everyone to see. Is there anyway this can be avoided without having to create seperate playstore accounts for every user?