Product Replacement Transition

I have a series of parts that are going to be replaced with new parts. Is there a way in Optimizely that I can have the base items there but not viewable until we sell out of the old part?

Say I have part A and part B, once I sell the last part A I want part B to be viewable in the categories/search and orderable but not before it is sold out.

I do understand that I could designate part A as Discontinued and part B as its replacement part. The thing that I don't want is that part B show before part A is sold out. We are looking for a seamless transition.

Is there a way that I could get this to work in this manner?