Need to show seen bar in front of slots bar

I have used Excel since 1996 and most of my chart requests have been relatively simple, but this problem has me stumped.

We are tracking medical appointments over time for 9 providers.

Each of our providers has X slots in a month. X varies from provider to provider and month to month.

Each of our providers has Y completed appointments (seen) for that month. Y also varies for each provider and each month.

Providers are along the X axis. Slot and seen counts are on the Y axis. Each month is a separate set of vertical bars.

The first edition of this chart shows X and Y side by side for each month. That gets pretty cluttered after 3 months of history. Nine providers with 6 bars each is a mess.

We want to show slot counts instead of percentages because we want to differentiate between providers with 8 slots in a month vs providers with 150 slots in a month.

I want to show Y in front of X for each month. That would display one vertical bar showing X for each month with Y as a lighter color in front. A stacked bar chart won't do it because it converts it to a percentage. How can I do this?