Make a group, add arches to the group. Apply the effect to the group. Do not check the box next to the model group name on the model groups window.
A group is just a model with different dimensions.
I like to use the Bars effect for chases on groups. Use 2 or more layers.
On layer 1 start the Bars effect Left to Right
On layer 2 start the Bars effect Right to Left before the first effect ends.
If this doesn't work, I can remote session show you how to do it.