Project velocity with issues from SCRUM and KANBAN teams

Hi community,

I would kindly ask for your help regarding this topic:

I want to display the 2 week average velocity of our project. However, half of the issues are in Sprints, half of them are not (since we work mixed in SCRUM and KANBAN).
I would like to have the Velocity as a column, and the last x Sprints on the rows.

However, if I simply do this, the calculation of course runs for only those issues that were indeed in the sprint.

If I overwrite the sprint member with a tuple, then I loose the start and end date, and get no meaningful result.

I was experiencing with an extended tuple but couldn’t get it working since there is no one member on [Time] that would fit perfectly with our sprint close and end dates, and I can only get a set of members

(
  [Measures].[Story Points resolved],
  [Sprint].DefaultMember,
  [Time].[Day].DateMembersBetween(
    [Sprint].CurrentHierarchyMember.GetDate('Start date'),
    [Sprint].CurrentHierarchyMember.GetDate('End date')
  )
)

I also tried to create a new [Time] hierarchy with 2 weeks that would start and end on the same days as our sprints, but somehow I cannot refer it either.

(
  [Measures].[Story Points resolved],
  [Sprint].DefaultMember,
  [Time.2 Weeks].[2 Weeks].DateMember(
    DateAddDays(
      [Sprint].CurrentHierarchyMember.GetDate('Start date'),
      7
    )
  )
)

I appreciate your support.

Thanks,
Márton