Hi Steve,
If you intend to use iceScrum for anything else than software project management & development then I am afraid that it will not be smooth.
Unfortunately I am not very familiar with IS/IT management, and I’ve heard of ITIL but I don’t have enough experience with it to be sure how it translates in terms of Agile methodology and more specifically to Scrum.
Thus, I’ll try to rather focus on what I know: iceScrum.
– It is not possible to define dependences between items of different projects.
– An iceScrum team can work on several iceScrum projects, a project have one and only one team working on it.
– There is one priority list (product backlog) per project
– In addition to the members coming from the team (ScrumMasters and Team Members), every project has its own members, namely Product Owners and Stakeholders. Every role has associated permissions, see https://www.icescrum.com/documentation/roles-teams-projects/
Whether there should be only one iceScrum project (hence one priority list) for one team, or separate iceScrum projets (each having its own priority list) is really dependent on the context.
I hope that helps!