Is it OK to vote at more than one homegroup?
Is it OK to belong to more than one homegroup and vote on the business issues of both?
Typically people are encouraged to have one home group, not necessarily for recovery sake, but for AA "business" sake too. This is not "AA Policy" but simply a custom within the fellowship. Individual groups may approach the subject differently from each other.
Usually, your voice in AA business is through your homegroup which likely sends a representative to your district or intergroup to vote on how your group feels about broader AA business.
The idea of having your voice heard more than once through multiple homegroups could theoretically lead to individuals having undue influence.
In many, often rural, places groups meet perhaps once a week and a person ends up "joining" more than one group so they can get to more meetings. In this situation individuals may want to refrain from voting more than once on issues that affect more than the single group. This would keep it closer to the democratic principle of "one man, one vote."
For instance, if an issue is being decided for your area, like where to hold a conference, it might be best to vote on the issue at only one group. But if each of your homegroups votes on which type of coffee to buy there wouldn't seem to be a good reason not
to vote on the issue in each of your groups as it couldn't affect AA at a level beyond the individual group.
This is mostly all theory though. Each group is the highest authority in AA and is free to decide who votes on what.