Macrons over vowels

If it's not too much trouble, can vowels with macrons (horizontal lines, similar to the circumflexes, but completely flat) be added to the special characters list?

I'm a Latin teacher and I'd like to use zoho to write handouts, quizzes, tests, etc... but I would need to include long vowels (i.e., a, e, i, o, u, and y with macrons).

I also want to start an online collaboration with other Latin teachers, which would require macrons.

Michael Stewart