Master pages in Indesign are always seen as on the bottom of the object stack. However, you can use layers in Indesign as well. This somewhat breaks the object stack logic. Layers in Indesign allow you to stack any object, master page or otherwise.
- new document
- add a new layer via the Layers Panel
- Move edit the Master Page
- highlight Layer 1 in the Layers panel and draw a filled rectangle.
- Highlight Layer 2 in the Layers Panel and draw another filled rectangle.
- Switch to the document page
- highlight Layer 1 in the Layers Panel and draw yet another filled rectangle
You'll end up with stacking similar to this....
The magenta rectangle is on Layer 2 on my Master Page. The yellow rectangle is on layer 1 on the master page. The cyan rectangle is on layer 1 on my document page.
So, while master pages are always seen as the bottom of the object stack, layers take precedence and will allow you to stack things above a document page if you place objects on higher layers.
In your scenario, you could place the text on the master page on Layer 2, and then place backgrounds on Layer 1 in the document pages.
An important note is that you can apply master pages to other master pages. It's possible to have Master Page B which has Master Page A applied to it. This can assist in keeping any design fluent while maintaining common items.