[Typo3] customize template for more instances

[Jane Larsen]

Can I make a template that will be used on several subtrees in my
Typo3 install (3.7.0) where users can change some visual element,
likely a banner (fixed size for all uses) so that every instance of a
subtree has their own banne, placed in the same template (copying the
template could be an option)?

My idea is that induvidual user groups must use my template, but they
may change the banner preferably by them selves but could be main
administrator too, if I can figure out how to change the banner easily
when needed for the individual user group...

//Jane Larsen