Use a function to do it. On a standard module add this.
Public function IsKitExists(pComp, Paramarray p() as variant) as boolean
Dim sConcat as string
Dim var as variant
Dim bolreturn as boolean
'concatrnate each kit
sConcat="/"
For each var in p
sConcat= sConcat & "/"
Next
'test for duplicate kit
For each var in p
Bolreturn=(instr (sConcat,"/" & pComp & "/")>0)
If bolreturn then exit for
Next
IsKitExists=bolreturn
End function
You pass the kit to compare followed by list of kits to compare with.
Now you call the function to validate:
If IskitExists(me.part1b,me.part2b, ...) Then
'part already exists
Else
'kit does not exist so Okey
End If