Help targeting a player with specific tag in specific coordinates and changing their score?

I've been working on a mini game for a while now. It is a four player game and each player is set to the same team ("NonHostile" to prevent hostile mobs from attacking the players) but given different color tags (e.g. red, green, blue, yellow).

I am trying to add 1 to their score when they enter a specific area. I used to be able to target them when they were on separate teams by using this command:

• /scoreboard players set @p[55,56,20,2,team=blue] one 1

With the switch to tags, it doesn't seem I can just replace 'team' with 'tag'. I've tried both of these commands: */execute @p[55,56,20,2] ~ ~ ~ /scoreboard players set @a[tag=red] one 1 */execute @a[tag=red] ~ ~ ~ /scoreboard players set @p[tag=red,55,56,8,2] one 1

Both certainly do not work. Please help. I NEED to finish this thing.