A pipe with two wall thicknesses in the same spec

Dear experts

I need to create a piping spec which includes a pipe 6'', sch 80 and  a pipe 6'', sch xxs. My question is:
How to create a specification having two wall thicknesses for the same NPS?

Thank you in advance

Dear experts

I need to create a piping spec which includes a pipe 6'', sch 80 and  a pipe 6'', sch xxs. My question is:
How to create a specification having two wall thicknesses for the same NPS?

Thank you in advance