TYPO3: configure available types for tx_news content element relation - typo3

Question

Is it possible to configure which content element types are available for the content elements relation in tx_news records?
I have a backend layout which allows only gridelements in tt_content. The regular content elements are only allowed within a grid elements container.
Currently I face the problem, that in news records it's only possible to add grid elements:
I'd like to allow only some specific content elements in news records.
Update:
The above mentioned restriction is done via TSConfig for the BackendLayout:
mod.web_layout.BackendLayouts {
1 {
title = Standardseite
config {
backend_layout {
colCount = 1
rowCount = 1
rows {
1 {
columns {
1 {
name = Content
colPos = 0
allowed = gridelements_pi1
}
}
}
}
}
}
}
}
When I remove the line allowed = gridelements_pi1, all content element types are available again.
But regardless of the allowed setting for backend layouts I'd like to have just a small subset of content element types available for news records.

Answer 1

Sometimes the solution can be so simple and obvious! Thx for hint, Georg Ringer!
Just override the settings for the news sys folder:
[45 in tree.rootLineIds]
# this changes the allowed CTypes. Add more as a comma separated list
mod.web_layout.BackendLayouts.1.config.backend_layout.rows.1.columns.1.allowed = textmedia
# this sets the default CType to prevent an error with INVALID VALUE ("text")
TCAdefaults.tt_content.CType = textmedia
[global]
By the way, an even better solution would be to use TCEFORM.tt_content.CType.removeItem = ..., but this would require to update the list each time you add a new CType.