Graham tiaxgame Yes you can by using {% include 'subfolder/filename.anything' %}
and If you want you can split it into multiple parts
1/ all files have to be in _xtgem_templates or sub folders of it
2/ care must be taken to split the files in the right place to preserve the context
for example I just tested by splitting out the macro that outputs the guest book entries I had to include the line under the macro that calls it in the split
3/ keep a copy of the original incase of errors