IDM version 3.0.1

Is there a way to restrict access to a workflow to managers only?
(A manager in this case would be anyody who has direct reports.) Maybe
there's a dynamic group or similar defined already which could be assigned
as a trustee to this workflow?
Currently the workflow form is available in the "request a resource" and
also in "request a team resource" menus on the left hand side of UserApp.
We only want it to be available under the "request a team resource" and
not under "request a resource". (Currently only managers with direct
reports are able to see the "request a team resource" menu, so there must
be a way to determine who's a manager).
What's the best/easiest way of doing this? Thank you,

Csaba Borza