Hybris: How to restrict a component to multiple item types?

Question

In our application, we assign UserGroup to users in order to restrict scope. For this, we make use of B2BUnit as a type. However, we have Customers, Suppliers, and Partners as sub-groups of B2BUnit.

Problem Statement: We want to restrict the UserGroups to only Customers and Suppliers, and NOT the Partners.

I have already tried 'restrictToType' This only allows us to restrict the entry to one particular sub type, not a set of types.

<wz:property qualifier="userGroup">
    <wz:editor-parameter>
        <wz:name>restrictToType</wz:name>
        <wz:value>B2BCustomer</wz:value>
    </wz:editor-parameter>
</wz:property>