Never the Twain Should Meet

Two elder magi admire a maga's menagerie and want to visit. Both are politically powerful enough to suggest when they will come and, unfortunately, both select the same week to visit. The problem is that the magi hate each other, and have a history of declaring Wizard's War against each other. They have declared so many Wizard's Wars, often not doing anything besides declaring, that the maga is not even sure if one is currently underway. Regardless, the maga must somehow decline one invitation, which will surely lead to resentment and reprisal, or manage to host both magi and somehow keep them apart.