When I was a DOORS consultant I got asked this question reasonably often. In DOORS, it is possible to do this through triggers. However, in practice it is rarely anywhere near as useful as people think it is. There are a surprising number of cases where people need to create an entry but simply do not have all the "mandatory" information at the time of creation, so there is a risk that nothing gets entered, rather than just something incomplete. And then if you do force people to enter a value, how do you know it is valid and not just something they put in to satisfy the condition? For example, entering "asdf" into a text field or just picking a random value from a list.
So, in general, this is nowhere near as good an idea as it at first seems. It is prone to significant abuse. Better to have a process in place that ensures that requirements cannot pass review without valid (and validated) values.

Hi Chris,

While it was possible in RRC 2.x to indicate that an attribute was mandatory, that feature does not currently exist in the 3.x and 4.x versions of RRC.

And I do not know of any way to restrict artifacts created from a template as you describe.