Group criteria xPath to get multiple object types as members

This controls the membership of my groups. With this xPath, the members are the Groups.

/Group[PARENT_ORGANISATIONS_ID = '750547d8-8147-4c74-85b1-c1ec2bded963']

I also need the membership of my group to contain users.

/Person[Description= 'Constant']

So what i need, is the entire xPath where both groups and users are contained.

This is not correct, but this is what i wan't to do.
[(/Group[PARENT_ORGANISATIONS_ID = '750547d8-8147-4c74-85b1-c1ec2bded963']) or (/Person[Description= 'Constant'])]

any pointers`?

/Frederik Leed