So, interestingly, this partially works but only under special conditions.
If I have a single command such as:
${workspace_loc:/${ProjName}}\xxx
The command succeeds with a path such as:
C:\Projects\aaa\bbb\xxx
But, if I add an ampersand with two commands:
${workspace_loc:/${ProjName}}\xxx & ${workspace_loc:/${ProjName}}\yyy
The slashes are removed and the command fails with a message such as the following without any slashes to separate the directories:
C:Projectsaaabbbxxx: not found
However, if I put absolute paths in place of ${workspace_loc:/${ProjName}}, it will properly format and execute both commands.