re-routing vent line

I previously posted on cutting a cast iron waste line in the attic to tie in a vent, but I might have an alternative to avoid doing this, so here's my dilemma. I'm trying to eliminate a soffit in my kitchen. In this soffit runs a vent line horizontally (parallel to the soffit). This vent pipe picks up the 2 bathroom sinks on the upper level of my split level house. The vent line ties into the main waste stack in the soffit(like this)
I____vent_______________III I III I III I III waste stack Osink III I III
Can I reroute the vent line up to the attic between the wall studs, run horizontal in the attic, then back down between the wall studs to tie into the waste line (like this)
I________vent_____________I III I I III I I III waste stack I I III I I_________III Osink
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Sorry about the diagram, let me try it again.

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Sorry about the diagram, lety me try again.
Presently
I______vent_______III I IIII I III waste I III stack I III Osink I
Can I do this?
I_____vent___I III I I III I I III waste I I III stack I I_____III Osink I
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Mikepier wrote:

It's still as clear as mud :-)
Does the waste/soil stack extend thru the roof?
Where are the bath fixture connections in relation to everything else?
Could you create a line diagram in Paint or similar and upload a .jpg to PhotoBucket or similar?
Jim
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Sorry about the confusing multple posts. When I originally posted this message with a line diagram, it did not come out right , so I deleted the message. But to answer your question, there is nothing else connected to the stack upward, it just goes through the roof. The bath fixtures are on the second floor. Those are the highest drains in the house. I'll try to post an image later.
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I previously posted on cutting a cast iron pipe to tie in a vent line, but I might have an alternative to avoid doing this, so here is my dilemma. In my kitchen soffit runs a vent line horizontally (parallel to the soffit) that picks up the 2 bathrooms on the upper level of my split level house. This vent line ties into the main waste stack in the soffit. I would like to eliminate the soffit, which means re-routing the vent line. Can I route the vent line up to the attic between the wall studs, go horizontal, then back down again between the wall studs to tie into the main stack?
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