Varying participant padding

Question

is it possible to have varying participant padding. I would like to be able to have a group of few participants closer to each other and the rest of the participants at constant spaces.

To illustrate

@startuml

skinparam ParticipantPadding 200

skinparam MaxMessageSize 200

participant A

participant B

participant C

participant D

' spacing between A & B is 100 pixels

A -> B : Msg 1

' but spacing between B & C is 200 pixels

B -> C : Msg 2

' and spacing between C & D is 200 pixels

C -> D : Msg 3

@enduml

Output

@ http://www.plantuml.com/plantuml/png/PSt1QeGm4CRn-pp5dDfJ8TfR3qKJhuBG9nZD8A4QWXDPsQVVX1LMr-F_ItvC9P6MkCuJWFmx7sYX6RiqkS45yh4ZQvqViLJg-AEbhMKH6ldFtVdv6buAwtFgSvfpDW2VA866VAZdU6FsMEC7QdI2XL8OtCQJ0DJuzPlM7snbn2ApVeqNgXCrcPO7gZCrEoqp9Mylr2JQl5EJQRFJRu2AlLtdwG40

I would like to see spacing between A & B at 100px and spacing between B to C at 200 px and C to D at 200px. Is something like this possible?

Thanks