To limit who sees the Ticker you have created, you must create an audience containing those users who need to see it and then assign that audience to the ticker. See articles below:

1) Make sure that 'Is Global' is deactivated. This is to ensure that the ticker is only seen by a specific audience.

2) Select the Audience from the drop down list that you have already created.

How do I create an audience?

Creating a Ticker (Step 3).