Would like to be able to specify included files

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Steps to reproduce
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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,
Phil

Actual behaviour
Tell us what happens instead

Client configuration
Client version:
Client operating system:

Server configuration
Operating system:
Web server:
Database:
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.