you should not try that at all. There's no guarantee that different Informatica repositories will never use the same table names (and in fact I've heard that such a "guarantee" would already be violated for years now).
Informatica always states in its Installation And Configuration Guides that you have to create one schema per repository, no matter whether it's a domain or an application repository. It's that simple.
And if your DBAs don't want to believe, raise a service request at Global Customer Support, they will confirm this statement (at least I'm 100% convinced about that).
As Nico rightly said, you should not use same schema to host different Informatica application services/repositories.
Yes I agree, I wanted to see if such options available. I don't want to do anything out of the recommended options. I requested to create separate schemas for each services. Thanks Hitesh & Nico.