XML Data Template Parameter definitions - Is it possible to pass a list of items as a parameter

I have a requirement to pass a list of items as a parameter for a BI Publisher report using the XDODTEXE executable.  Users would like to pass a list of projects on the concurrent program, so I've defined a conc pgm parm with 240 Characters as the value set.  User wants to populate freeform with a list of projects, e.g. 'ABCD', 'EFGH', 'JKLM'

Report currently allows a single project and functions properly.  Trying to modify to allow a list of projects, so that main query is something like:

select ...

from pa_projects p

where p.segment1 in (:p_project_list)