Hi,
Yes, you can create business rules in the entity to allow you to hide the fields.
It might seem a bit daunting at first but when you get into it it's not too bad to use and very useful.
What you need to do is set a condition (If Project contains data) after that you add your Then and Else statements
If Project contains data
Then
Task is visible
Else
Task is not visible
Project and Task being the fields within the entity that you what you make visible or change.
The most tricky part of business rules is the activating and deactivating.
For example, there might be an existing business that is nearly what you want so you can copy that and then create your own rule.
In this case you need to deactivate the rule you want to copy, save it as a new rule, and then activate the main rule again.
You can then work on your own rule, save it, validate it, and then activate it.
Rules won't work until they are activated.
Hope this helps,
Jason