Some very early 2020 Euro news...
The host cities were divided into six pairings, established on the basis of sporting strength (assuming all host teams qualify), geographical considerations, and security/political constraints.
Each qualified host country will play a minimum of two matches at home. The group venue pairings is as follow
Supposedly if all the host nations qualify the groups will look like this
G1 - Italy, Azerbaijan, 3rd team, 4th team
G2 - Russia, Denmark, 3rd team, 4th team
G3 - Holland, Romania, 3rd team, 4th team
G4 - England, Scotland, 3rd team, 4th team
G5 - Spain, Rep Ireland, 3rd team, 4th team
G6 - Germany, Hungary, 3rd team, 4th team