Changing a module GP from other maps


I have the following situation

There are a bunch of (numeric) properties associated with each player that get updated every turn (think income and current resource level). I would like the ability to modify the income and the levels to live in each player’s board. I thought of two solutions to implement this but each one has a different problem:

[] Make the properties live in each map (grouped by player). The global command that increases turn is able to change update them correctly. However, if the individual maps are not open, they do not get updated.
] Make the properties live in the module. Then, I cannot find an easy way to have buttons in the individual map toolbars to modify them (for example, by relaying directly to the Change-Value Toolbar). If I put a GKC in the individual map, it doesn’t get relayed to the GP. The only way I found how to do this is with a phantom piece in the map that has a Set Global Property.

Is there any way to solve this without the phantom piece?