See here Source node override with templates (netxms.org) (https://www.netxms.org/forum/general-support/source-node-override-with-templates/msg32957/#msg32957)
With the new Collector object class I think this will be even more useful.
There's still no easy way. Theoretically there could be an option to set source node from nxsl (and may be some hook script to set this right when template is applied). And there are many other things which can not be done from nxsl, so there's a lot of work to improve that.
So yes, it's possible to configure Script DCIs and do data collection that way.
Or another possible workaround is to have nxshell script that is executed as server's action and that script would change source node.