Something like?

ILM Visual Effects Supervisor
Dennis Muren

Visual Effects Supervisor - ILM
Dennis Muren

Or variations similar to these.

Just wondering?

This rule comes in: "List individual credits only, not company name credits. Exception: If a company name heads a group of crew, use the Group divider to enter the company name."

So it's fine by that rule (I have to say that in those examples I wouldn't add a group divider and I would enter the info in the custom role field).

If it's credited like this, it isn't allowed by that rule:

Visual Effects Supervisor for ILM        Dennis Muren

It also depends on how the lay-out of the credits is set. If all credits are written that way then I certainly wouldn't add a group divider. On the other hand I wouldn't/couldn't vote against it either. For example:

Art Director
Jim Teegarden

Make-Up
Joel Harlow

ILM Visual Effects Supervisor
Dennis Muren

etc.

I'm also beginning to think what's the actual use for group dividers in the crew table? Is it just for simulating the the actual credits? Is it for the context? Maybe both? Or something else? The introduction of group dividers in the crew table makes contributions more confusing and I'm more and more in favour for the local use of group dividers (only in the case of the crew).