Selecting checkboxes by drop-down list

Hello I am a newbie in Excel VBA. I have a drop-down list with Value "Y" and "N", and I have 5 checkboxes. My idea is, when I select "Y", the checkbox1,2 and 3 are selected, but you can deselect checkbox 3 manually. If it's "N", it doesn't matter.

I tried to use ActiveX control checkboxes "LinkedCell" to the drop-down list, but when I deselect checkbox 3, checkbox 1 and 2 got deselected too. I am wondering if someone could help me with my problem.

If I cannot do it in ActiveX controls, can I do it in Form Controls checkbox? Thank you very much!