Position of big time signatures in scores

I would like to have big time signatures appear between some orchestral groups only but not between all of them. I found a way to define these positions by checking the boxes of system objects. However this will bring up all other system objects to these positions as well.
Is there a way to control the position of time sigs only?

Engrave mode?

The control over this isn’t perfect, you have to use a bit of a workaround at the moment. Set the time signatures to appear at the group positions instead of system object positions, and then manually create groups based on where you want them to appear. When you make groups, it’s going to mess up the bracketing so that it is no longer correct, and then you’ll have to go to engrave mode and fix the brackets.

Thank you! – Would I then have to fix the brackets manually on every page?

You might, it depends on whether you see all staves on the first page or not. If there are some staves that don’t appear on the first page for whatever reason, the bracketing may be wrong when they get added to things partway through, and you’ll need to make adjustments at those spots. Usually staves disappearing is not a problem as it knows how to handle that.