Would like to be able to specify included files

Please help us by providing the following info. Before posting please make sure that you're running the latest available version for your oC release: https://owncloud.org/changelog/ + https://owncloud.org/changelog/desktop/

Steps to reproduce

Expected behaviour
Tell us what should happen

If possible, I would like to include a file for sync of the form .filetoinclude while excluding all others of the form .xxxxxx.
Is this possible and/or could it be included as a feature in the future?
I already exclude .xxxxx from sync and I know one could add all the .????xxxx filenames to the exclude list except .filetoinclude but that seems like a lot of work and susceptible to errors.
Any ideas appreciated and thanks,

Actual behaviour
Tell us what happens instead

Client configuration
Client version:
Client operating system:

Server configuration
Operating system:
Web server:
PHP version:
ownCloud version (see ownCloud admin page): 9.1.5
Updated from an older ownCloud or fresh install:
Special configurations (external storage, external authentication, reverse proxy, server-side-encryption):

ownCloud log (data/owncloud.log)

Please paste possible errors in the following code block, see https://central.owncloud.org/t/how-to-find-webserver-or-oc-logfile-enable-php-logfile/808 for more info

This is not currently possible and I did not see anyone requesting this yet.