An idea about temples

I found it quite strange that each faction was only limited to the 3 temples or so it can build when historically they all had a whole pantheon. In particula I find it strange that when the Julii capture a Vulcan (say) temple they can no longer upgrade it. So my idea was to mod the building files so that all nations can UPGRADE all temples from they culture. They way to do this is to leave the tier 1 temples unaffected but make the tier 2-5 temples available to the whole culture. e.g. the tier 2-5 Vulcan temple would say:

temple_of_forge_temple requires factions { barbarian, greek, roman, }

instead of:

temple_of_forge_temple requires factions { dacia, seleucid, romans_scipii, }

This still means the temples cannot build from scratch, but they can be upgraded once captured.