IdStory Identity Manager

Affected version: 7.6.0
Attribute mapping for synchronization.
I would like to map one schema attribute to multiple identity attributes. This can't be done, the error message says "Record is on collision with another unique record. ux_sys_attr_m_attr (name:ux_sys_attr_m_attr)". I think there is no reason to restrict attribute mapping in this way.

Example use case:
The HR system has the identifier "ID_IT" of the user. I want to map this attribute: 1) to the EAV attribute "id_it", 2) to identity username with some additional transformation.