Multiple Startup file inclusion

Hello,
I am working on a generic project targeting three different STM32 boards. To select the appropriate board, I am using #ifndef directives. My question is, how can I include and configure multiple startup files in Keil for this setup? Is it possible to do so, and if so, how can I properly configure them? Are there any limitations or considerations to be aware of when using multiple startup files for different boards?

Thank you in advance for your help!