Using Linked-Entity in addCustomFilter

At this moment I know how to use the addCustomFilter in combination with addPreSearch (and the remove variants). All this works perfectly when passing a filterXml like:

    <filter type="and">
      <condition attribute="name" operator="eq" value="test123" />
    </filter>

But I just can't figure out how to use linked-entities in the addCustomFilter and whether it is actually possible. I've tried the following:

    <link-entity name="account" from="accountid" to="parentaccountid">
      <filter type="and">
        <condition attribute="name" operator="eq" value="test123" />
      </filter>
    </link-entity>

It is still the same filter but it is now placed on the parent account of the account. With this filterXml I want to get all the accounts that have the account 'test123' as the parent account.

The problem is that the filter doesn't work in the addCustomFilter but it does return results in the AdvancedFind.

Is there a way to use linked-entities in the addCustomFilter method, if so what am I doing wrong?