rabbit73 mentions inserting and the expense of this.
I hope to dabble in that along with going for some Springfield stations myself. In my case inserting 17 & 22 along with 49 into my main UHF going to KC, and bring along the VHF for 8 & 13 as it is now with the UVSJ.
eBay has a chap selling custom items from Europe. I have not really tested it yet.
In theory you could insert 17 & 22, I would think KMOS would come through easily on the backside of your UHF.
They might be able to insert 10 into your 8 & 13.
IF this was thought through it
MIGHT help eliminate the trouble combining.
BUT this is still uncharted territory for me.