Select plane from selected part in assembly

Option Explicit
Const ReqPlane              As Long = 3
Dim swApp As SldWorks.SldWorks
Dim Part As SldWorks.ModelDoc2
Dim boolstatus As Boolean
Dim longstatus As Long, longwarnings As Long

Sub main()
Dim swSelMgr As SldWorks.SelectionMgr
Dim swComp As SldWorks.Component2
Dim swCompModel As SldWorks.ModelDoc2
Dim swFeat As SldWorks.Feature
Dim swCorrFeature As SldWorks.Feature
Dim PlaneCount              As Long
Dim bRet As Boolean

Set swApp = Application.SldWorks
Set Part = swApp.ActiveDoc
Set swSelMgr = Part.SelectionManager

If swSelMgr.GetSelectedObjectCount2(-1) = 0 Then Exit Sub

Select Case swSelMgr.GetSelectedObjectType3(1, -1)
Case swSelCOMPONENTS
    Set swComp = swSelMgr.GetSelectedObject6(1, -1)
Case Else
    Set swComp = swSelMgr.GetSelectedObjectsComponent4(1, -1)
End Select

If swComp Is Nothing Then Exit Sub

Set swCompModel = swComp.GetModelDoc2

Set swFeat = swCompModel.FirstFeature

Do While Not swFeat Is Nothing
    If "RefPlane" = swFeat.GetTypeName Then
        PlaneCount = PlaneCount + 1
        If ReqPlane = PlaneCount Then
            Set swCorrFeature = swComp.GetCorresponding(swFeat)
            If swCorrFeature Is Nothing Then Exit Sub
            bRet = swCorrFeature.Select2(False, 0)
            Exit Do
        End If
    End If
    Set swFeat = swFeat.GetNextFeature
Loop

End Sub

Dim swApp As SldWorks.SldWorks

Dim swModel As SldWorks.ModelDoc2

Dim swSelMgr As ISelectionMgr

Dim swSelGroup As New Collection

Dim swComp As SldWorks.Component2

Dim swFeat As Feature

Set swApp = Application.SldWorks

Set swModel = swApp.ActiveDoc

Set swSelMgr = swModel.SelectionManager

For i = 1 To swSelMgr.GetSelectedObjectCount

    swSelGroup.Add swSelMgr.GetSelectedObjectsComponent3(i, -1)

Next i

swModel.ClearSelection2 True

For j = 1 To swSelGroup.Count

     Set swComp = swSelGroup.Item(j)

     Set swFeat = swComp.FeatureByName("X Plane")

     val = swFeat.Select(True)

Next j

Dont completely know what you were looking for but that selects the "X Plane" of every selected component. Does not leave the components selected though. If you wanted both the components and their plane selected you just have to delete "swModel.ClearSelection2 True"