Sounds like a stupid question, as the answer is already in the title. If a company has only RedHat Enterprise Linux as allowed / supported Linux platform (be it for a support model requirement, ISV certification, management tooling support or what not) how could or would Gentoo still play a role in it.
But the answer is, surprisingly, that Gentoo can still be made available in the company architecture. One of the possible approaches is a virtual appliance role.
Virtual appliances are entire operating systems, provided through VM images (be it VMDK or in an OVF package), which offer a well defined service to its consumers. More and more products are being presented as virtual appliances. Why not - in the past, they would be in sealed hardware appliances (but still running some form of Linux on it) but nowadays the hypervisor and other infrastructure is strong and powerful enough to handle even the most intensive tasks in a virtual guest.
Gentoo is extremely powerful as a meta-distribution. You can tweak, update, enhance and tune a Gentoo Linux installation to fulfill whatever requirement you have. And in the end, you can easily create a virtual image from it, and have it run as a virtual appliance in the company.
An example could be to offer a web-based password management suite. A Gentoo Linux deployment could be created, fully hardened of course, with a MAC such as SELinux active. On it, a properly secured web server with the password management suite, with underlying database (of course only listening on localhost - don't want to expose the database to the wider network). Through a simple menu, the various administrative services needed to integrate the "appliance" in a larger environment can be configured: downloading an SSL certificate request (and uploading the signed one), (encrypted) backup/restore routines, SNMP configuration and more.
If properly designed, all configuration data could be easily exported and imported (or provided through a secundary mount) so that updates on the appliance are as simple as booting a new image and uploading/mounting the configuration data.
Building such a virtual appliance can be simplified with Gentoo Prefix, multi-tenancy on the web application level through the webapp-config tool while all necessary software is readily available in the Portage tree.
All you need is some imagination...