restoring session with pivoting

[EmilioPanti]

Hi,

I'm trying to understand what happen to sessions if one of them dies in a pivoting scenario.
Let's consider the following example:

We have 3 hosts: A, B, C.
Host A can see only Host B.
Host B can see Host A and Host C.
Host C can see only Host B.

The idea is to attack Host A, use pivoting to attack Host B, and then again attack Host C through A+B. (A -> B -> C)
We do pivoting with autoroute module (post/multi/manage/autoroute), and all sessions are meterpreters.

This is the scenario after all the attacks have been done:

Host A: session "1"
Host B: session "2" via session "1"
Host C: session "3" via session "2"

If session "1" dies, I can't reach the others.
And if I try to re-estabilish a new session on Host A, let's say session "4" now, I'm still not able to reach sessions "2" and "3" through the new session "4".

From the msfconsole command "sessions" I can clearly see the new indication

Host A: session "4"
Host B: session "2" via session "1"
Host C: session "3" via session "2"

so opening a new session on Host A won't automatically update the pivoting correlation. What can I do to solve this scenario?
Is there a way to replace the pivoting indication into an updated

Host A: session "4"
Host B: session "2" via session "4"
Host C: session "3" via session "2"

manteining the sessions "2" and "3", or am I forced to let die sessions "2" and "3" and re-estabilish them once again via session "4"?

I hope I made it clear.