how to make customer NOT able to order certain variant without ordering the specific one first

hi, i am selling pillows with matching pillowcases (unique shapes). but sometimes customers always order the pillowcase without ordering the pillow. can you give me some suggestions on how to avoid this happening?

thank you.

Hi @uksll ,

Your current options might be a bit confusing for your customers. Could you please clarify which choices are available for your Pillows (e.g., color) and Pillowcase (e.g., shape, color)? Also, is there any connection between the Pillows and Pillowcases? Do you offer them as a set, as separate products, or both? Once I have this information, I can provide a more suitable solution.