Dimension between different elements/references

Hi All,
Is there away or node i can use that can dimension between different references?

I can get them to work independently ie All AutodeskDB References into Dimension By Reference or all the surfaces Dimension.ByFaces. however no luck as a combo.

Ideally i was hoping to reference stair surfaces(yellow) and a detail curve(red) to get the dimension on the right.



cheers KS