That approach is marginally better. It’s still arguably unclear. The store could be your mom’s favorite store to get special gifts from If you think using Gran

That approach is marginally better. It’s still arguably unclear. The store could be your mom’s favorite store to get special gifts from If you think using Grandma three times is too much, you could replace the first Grandma in the second sentence with “she.” For instance, “she, my mom, and I went…”