Preventing inferencing to other geometry

I have a mesh that was imported. I have created a face that slices through the mesh. these are in two separate groups. I want to create a spline on the face, using the mesh as a guide. I have turned on 3 point plane, tried setting the plane, etc. I can get the tool to inference the face (plane), but if I get too close or in the mesh the tool wants to inference to the mesh geometry and then becomes unattached to the face-plane and then I have spline control points going where I don’t want them. I have tried hiding the mesh and then showing hidden objects but it still wants to inference. I don’t want the spline to attach to the mesh, but i want draw the spline very near or through it on the face, using the mesh as a visual guide. Seems like there should be some way to prevent inferencing to geometry that is visible.