How do people handle using Outlook and Zoho Project calendar at the same time?

How do people handle using Outlook and Zoho Project calendar at the same time?

We have an ongoing problem in our organisation where we use Zoho Projects to plan all of our projects tasks and that also allows us to look forward using the workload report to see which of our consultants are overstretched etc and which are available.

However there's lots of activity that we do which isn't project based and that people put in their Outlook calendars. So the outlook calendar doesn't have a full view of what's in zoho and zoho doesn't have a full view of what's in outlook which means there is no single source of the truth.

So I want to know how people handle this because I'm using the outlook app in Zoho projects: when I create a task it creates an outlook calendar entry which is brilliant but when I update it in zoho it doesn't update it in outlook which is utterly useless to anyone because projects change all the time. how people deal with this problem?