swimmlane sensitive WIP-limits

As a Kanban teamlead I'd like to specify a work-in-progress limit based
on swimmlanes to enable the team to handle "prio-1-emergency-ASAP"-tasks
in a dedicated ASAP swimmlane whitout interfering the current WIP.

example:

• board has the standard 3 columns
• board has 2 swimmlanes: ASAP and OTHER
• WIP-limit on "in progress" is 3
• team is working on 3 tasks in OTHER (ASAP is empty)

now a real urgend issue is opened by support.
this issue should appear in the ASAP swimmlane and the team
has to start immediatly.
The WIP-limit of "in progress" does not allow to start the
work on a 4th issue...

Therefore I want to be able to set diffrent WIP-limit for
diffrent swimmlanes