Thank you journey-on. The WBTS in the Insight Volumes does allude to the Kingdom being all that Jehovah rules over as universal sovereign but it conflates this broader,more expansive truth with their mantra about the kingdom being a "heavenly government", a vehicle or agency that rules from heaven, that we pray to come and replace all human forms of government. They are being deliberately disingenuous about this and obfuscating this truth from the rank and file. They do this because they want the "other sheep" to believe that only those with the 'heavenly hope' have the prospect of being in the kindom and so only those ones have the right to partake of the emblems. The Society wants to hide the beautiful scriptural truth that ALL true Christians, whether professing and earthly or a heavenly hope, are in God's Kingdom now and will inherit the Kingdom, either in the "new heavens" or the "new earth" (2 Peter, Revelation 21) in the future. It's a deliberate doctrinal ploy to keep JW's blinded to the scriptural truth that there is no separation by the holy spirit between those with an "earthly hope" and a "heavenly hope". The nefarious GB wishes to blind 99% of JW's to the truth that they also "inherit the Kingdom" (the earthly realm of it) and are also in the "new covenant".
As for the oft-quoted words of Jesus "the Kingdom of God is within you" (which is a poor translation), I think the Society's explanation of the commonly perpetuated misunderstanding about what Jesus meant by this is quote sound. You can find their explanation about what Jesus really meant in their 'Reasoning' book.