how to force all the site collections & subsites' logos to referecne to the root url

I have a web application which contains 2 site collections and the site collections have subsites.

Currently the first site collection is deployed under the root:

http://servername

While the other site collection and its subsites have the following urls:

http://servername/SC2

https//servername/sc2/subsiteA

Currently all the site collections and subsites will have the same logo picture, but if you click on the logo it will redirect to the current site collection or the current sub site.

so my question is how i can force the logo to always redirect to the root site collection?
I know I can modify the master page for each site collection and subsite, but I'm asking if there is a more general approach that can affect all the current logos at once?