Changing specific checkboxes from tick to a cross

Hello!

I wanted to know how to change the checkboxes from showing ticks, to showing crosses, but only on certain checkboxes. There are a few I want to leave as ticks, but others I want to display crosses when checked.

I’ve managed to change all of the checkboxes to show crosses, but is it possible to have a mixture of boxes showing ticks and crosses?

Thank you!