Support Adding boosters to Velcro Blue Scout style scenario

[n0mad23]

With all the Velcro use I thought I'd pose this question to the larger community instead of PMing Sputnik. Maybe someone else will find this useful at some point.

Using the Velcro Rockets' scenario "X-15 Blue Scout" as an example, what I'm wondering is if it's possible (and if so how it's done) to attach boosters to the first stage. The challenge is that the first stage here is already "pretending" to be parallel burning with the X-15 that it's attached to.

Here's the Velcro scn:

BEGIN_DESC
Launch an X-15 with underslung rocket payload.  Use RelaseMFD to release.  Once the XLR-99 is ignited, pitch up to 50 degrees.  Once the XLR-99 is extinguished, pitch down to level with the horizon.  F3 to the first stage.  Hit "J" to jettison it, and throttle up to start the Blue Scout's first stage engine.


B-52 carrier ship is cruising at 500 mph (223 m/sec), altitude 45,000 feet (13.7km).  

END_DESC

BEGIN_ENVIRONMENT
  System Sol_ProjectX-15
  Date MJD 38263.9592091898
END_ENVIRONMENT

BEGIN_FOCUS
  Ship B-52_3
END_FOCUS

BEGIN_CAMERA
  TARGET B-52_3
  MODE Cockpit
  FOV 50.00
END_CAMERA

BEGIN_HUD
  TYPE Surface
END_HUD

BEGIN_MFD Left
  TYPE Map
  REF Earth
  BTARGET Edwards AFB
  ZOOM
  TRACK ON
END_MFD

BEGIN_MFD Right
  TYPE Surface
  SPDMODE 2
END_MFD


BEGIN_SHIPS
B-52_3:Spacecraft\Spacecraft3
  STATUS Orbiting Earth
  RPOS -4756028.11 4255389.50 142082.78
  RVEL -9.365 1.989 -407.079
  AROT -124.34 38.91 -110.85
  RCSMODE 0
  PRPLEVEL 0:0.377
  THLEVEL 0:0.471
  NAVFREQ 94 481
  RCS 0
  CTRL_SURFACE 1
  CONFIGURATION 1
  CURRENT_PAYLOAD 0
  SEQ 0 2 0.996119
END
X-15_XLR-99:Spacecraft\Spacecraft3
  STATUS Orbiting Earth
  RPOS -4756031.66 4255380.27 142084.01
  RVEL -9.365 1.989 -407.079
  AROT -124.34 38.91 -110.85
  ATTACHED 0:0,B-52_3
  PRPLEVEL 0:1.000 1:1.000
  NAVFREQ 0 0
  RCS 1
  CTRL_SURFACE 1
  CONFIGURATION 1
  CURRENT_PAYLOAD 0
  SEQ 0 -2 0.000000
  SEQ 1 -2 0.000000
  SEQ 6 -2 0.000000
  SEQ 7 -2 0.000000
  SEQ 8 -2 0.000000
END
Blue_Scout_Jr_Stg1:Velcro/Antares1A
  STATUS Orbiting Earth
  RPOS -4756029.44 4255380.68 142084.85
  RVEL -8.109 3.275 -406.201
  AROT -124.34 38.91 -110.85
  NAVFREQ 0 0
  CONFIGURATION 0
  PRIMEBOOSTER 0
  CENTERTHRUST 0
  IGNITENEXT 0
  IGNITE_WITH_CORE 0
  JETT_ON_MECO 0
  JETT_ON_EMPTY 0
  TIPOFF 0.0
  PADBIAS 1.00
  TGT_HEADING 90.00
  PARALLELBURN 1 X-15_XLR-99 0.0000 -0.8000 -2.0000 0.0000 0.0000 -1.0000 0.0000 -1.0000 0.0000
  STAGE Stg2 Velcro/Alcor Velcro/Alcor 0.00 0.00 2.67 520.00 0.00 1.00
  STAGE Stg3 Velcro/Cetus Velcro/Cetus 0.00 0.00 3.62 50.00 0.00 1.00
  PAYLOAD probe Velcro/Parts/dummy probe 0.00 0.00 5.80 7.50 0.00 1.00
  PAYLOAD PLF1 Velcro/Parts/BSJPLF1 Velcro/Parts/BSJPLF1 0.00 0.00 3.44 2.00 0.00 1.00
  PAYLOAD PLF1 Velcro/Parts/BSJPLF2 Velcro/Parts/BSJPLF2 0.00 0.00 3.44 2.00 0.00 1.00
  ENDSTAGE 
END
END_SHIPS

What's tripping me up here is that Stage 1's "parallelburn" with the X-15. Strap on boosters don't like to parallel burn with things already parallel burning and naturally I get a CTD if I attach strap-on boosters this way.

Any ideas?