Manually edit varying rebar dimensions / elements for using as constraints?

[PSmart17]

Is it possible to manually edit the dimensions of varying rebar sets?  The varying bar lengths want to be set not according to a slab edge but to the line in green. I hoped I could constrain to a reference plane or similar but that doesnt seem to be possible.  Would I be forced to just place individual bars, and if so can they be somehow grouped to act as a single set with rebar number 01a to 01d?

thanks

[jay_colcombe · Accepted solution]

Unfortunately, I cannot see away around this with splitting the slab so the edge can be used as a physical constraint