[Note: this post is old. You are probably already done with this project. However, I'm posting so other people can see my thoughts in the future, should they have the same issue.]
I couldn't imagine any easy method to do what you want to do. As Hartmut said, orthos are not intended for this.
Any of the solutions I propose below will take time to set up. Experiment to see if they work before implementing them. Depending on the size of your project, they might cost you time instead.
Using layers might help, especially if most of your isos are broken up by line number. If you have to update the drawing repeatedly, you could add a custom "Iso dwg number" property for piping components (Project Setup > Plant 3D DWG Settings > Plant 3D class definitions > Piping and Equipment > Pipe Run Component; "Add..." button). Since iso drawings are downstream from the project, I don't believe you could make any kind of parametric link for what iso drawing a pipe appears on to be sent back into the model. Therefore, you'd have to keep this custom property updated whenever you change iso drawing numbers.
To automatically space components out, I think you'd have to adjust the project spec so that each item's node is spaced out from its geometry. This might be a piping spec item or it could be something in the connection rules. Alternatively, you could specify that anytime anything connects in the 3D model, plant needs to automatically add an invisible component (similar to how a spec can require backup rings or spaces to be automatically added to a flanged connection when working with certain materials). The component would have nodes spaced out to whatever gap size you want, while it shows no geometry. The problem with either solution is you'd have to find some way to preserve the original geometry (otherwise a 6' stretch of pipe becomes a 4' stretch of pipe with 1' gaps on either side). How you can do this, I don't know.
To make the ortho tag automatic, you need some kind of property for the iso drawing number as mentioned above. Using that, you can create a new ortho tag. Go to the same place in Project Setup [the Pipe Run Component area] and use the "Ortho Annotation Setup" in the lower right corner to Add Annotation... and Edit Block..., assigning your custom property to the tag you want. This blog post explains something vaguely similar to what you want, except what you want to do in this instance is simpler.
Ultimately, it sounds like a headache. I'd badger your construction team until they let you get some kind of compromise, such as creating ortho views of various sections of the plant. They're asking a lot from you, even if they don't realize it.
P.S. One other solution entirely could be to use an iso drawing and make it look like an ortho. If you set up your iso style right, you can use insulation to imitate pipe thickness, making the centerlines dashed and hiding dimensions. You could make the Bill of Materials use part number and your custom iso drawing number property, change the iso tagging to automatically use your custom property (which takes some effort), add an Iso Message to each piping component with the drawing number called out, or manually tag each component in the "ortho" drawing. This might be the easiest solution. It won't look official, but if all they're fishing for is a more intuitive representation of iso drawings, it would work.
