problem with polyline overlay

I don't know if this is the right board to post this question, so please move it to the appropriate one if not :)

I'm currently working on a spatial network visualisation and in this regard i'm facing some problems with the respective polylines. I'm visualizing the lines according to a custom variable called 'strength', so stronger connections between points appear thicker and darker. In this respect I'm wondering, how I can manipulate the overlay of the lines, as in my example, the thiner and brighter lines are overlaying the darker and thicker lines, which is not what I want. Actually I want the dark lines to be on top of the bright ones, as they are more important.

I already tried to reverse the order of the symbology. The only solution that occurs to me is to paste a copy of the respective layer and use the definition query to include only strong polylines in this layer. This would solve my problem, but in order to fix the overlay for all symbol classes (which are 5), i would need to do this 45 times for all my 9 maps.

Is there another solution that would fix this overlay problem?

Thanks!!

PS:

here's a picture that describes it maybe a little bit better :)

Attachment 23198

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