Can change of FPS be partialized?

[BG Davis]

The recent addition of partial changes (changes to a selected portion of a clip) in eq2 filter (color, contrast, saturation, etc.) is very nice.
It would be wonderful to have the same function for the [Change FPS - speed up/slow down the video] function.  This effect is very useful in creating interesting videos, such as slowing the action at critical moments.
Any chance of this change being implemented?
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My thanks to Jan Gruuthuse and eumagga0x2a, whose advice and assistance have been a huge help.