Could you please be more specific about what do you mean by overlap. Are you looking for something like sheet swapping on selection such that the two maps get displayed in the same place on selecting the appropriate option?
In that case, you can refer to this link below:
Hi, What i mean by overlay is I would like to see map a and map b on the same geographical map. I would like to map a dots and map b dots on the same graph. Is that possible? I looked into dual axis but couldn't quite get that to work. I appreciate any suggestions you might have. Thanks again