One customer multiple products and SLA

One customer multiple products and SLA

Hi;

We support for multiple products. (Product x, Product Y, Product Z etc.)

My customers have multiple products. A customer is using the x product and the Y product.

SLA times of the products are also different.
For customer A;
X product SLA >> Diamon
Y product SLA >> Standard

When I try to define more than one SLA to a customer, there is an error you cannot define an existing SLA exists.

Do you have any suggestions on this subject?