Not answering your question, but more thinking of what is not possible.
To get a resource object attribute available for a team object based portlet would required to have the value be reproduced for a team (custom) attribute. You cannot use a virtual attribute because the parent of the team object is investment and not resource. Dave thinks you cannot use his method "How to put any dynamic values" to display in query based portlets and I don't think it cannot be used either in object based portlets.
You could use a gel script to populate the field. In order that to be support you would have to XOG in the value. I do not see team as an XOG object while team data is part of project data. Have not explored if custom team attribute values can be XOGed in. I do not see investments either as XOG objects, but assets, ideas, other work etc.
Unsupported direct db write with gel of custom team object attribute values could be possible. That would have to be tested if it then were available for your portlets.
You could test, by creating the attribute and manually entering the data.
I take manual data entry is out for production.