Hi there, we have a zip and link mattress (super king size, so 6 foot width in total) but wish to buy a zip and link memory foam topper(s) to go with it. We may separate the beds some day and want both to train their topper.Does such a thing exist? Or would be be best just buying 2 x 3 foot memory foam toppers and butting them up to each other on top of our current mattress?Many thanks for your advice.Best Regards, Claire Robinson