EnterWorks does support validation rules for repeatable attributes.
To assign multiple attributes to a validation rule:
Open the desired profile in the Profile editor, click Next, and open the Rule List tab.
Select the Validation Rule (or create a new one with Action > New).
Double-click the record or in the Action dropdown menu, select Edit.
The Define Rule Details editor will open.
In the Define Rule Attributes section, in the Action dropdown, click Assign.
A list of attributes will appear.
Click the checkbox next to the attributes to apply the same Validation Rule (with the same validation level).
The OK button is at the bottom of the list of attributes. You may need to scroll down to find it. Click the OK button and you will return to the Define Rule Details editor.
The new attributes for the Validation Rule will appear in the list.
Click OK to return to the Rule List tab on the Profile editor.
Click Save to save the changes to the Rule List.
A confirmation message will be shown.