ARM RealView linker: locating in any of several regions - linker

Question

Is there a way of allowing the ARM RealView/Keil linker to select from more than one but not all regions?
I can use the .ANY specifier to allow the linker free reign, and I can use a *(section_name) specifier to locate specific objects to a single region, but I would like to be able to have the linker select from several suitable regions.
To make it clear why this is desirable, I am using an STM32F4xx microcontroller with three distinct but contiguous SRAM regions on separate busses, and a further core-coupled memory region which is not bit-bandable or accessible by DMA. I want to use the smaller SRAM region for DMA to avoid bus contention and improve performance and deterministic behaviour. This region is inconveniently located between two larger regions and I want to be able to use either of the larger regions for bit banding while allowing the CCM memory be used freely for any purpose other than DMA or bit-banding. The regions are currently specified as follows:
RW_IRAM0 CCM_START CCM_SIZE
{
.ANY (+RW +ZI)
*(core_coupled_ram)
}
; SRAM1 112Kbytes (Buses: I, D, S, DMA)
RW_IRAM1 SRAM1_START SRAM1_SIZE
{
.ANY (+RW +ZI)
}
; SRAM2 16Kbytes (Buses: S, DMA)
RW_IRAM2 SRAM2_START SRAM2_SIZE
{
*(dma_ram)
}
; SRAM3 64Kbytes (Buses: S, DMA)
RW_IRAM3 SRAM3_START SRAM3_SIZE
{
.ANY (+RW +ZI)
}
Adding *(bitbandable_ram) to SRAM1 and SRAM3 is rejected by the linker with:
Error: L6223E: Ambiguous selectors found for ctransmissionschedulertask.o(bitbandable_ram) from Exec regions RW_IRAM1 and RW_IRAM3.
Similarly creating an overlapping region does not work:
; SRAM 192Kbytes
RW_IRAM_ALL SRAM_START (SRAM1_SIZE + SRAM2_SIZE + SRAM3_SIZE)
{
.ANY (+RW +ZI)
*(bitbandable_ram)
}
reporting:
Error: L6221E: Execution region RW_IRAM1 with Execution range [0x20000000,0x200045e0) overlaps with Execution region RW_IRAM_ALL with Execution range [0x20000000,0x20018608).
Currently my less-than-ideal solutions are:
to nominate only one region for bit-banding,
to make all the contiguous SRAM a single region (allowing DMA operations may occur in any memory making it less deterministic) thus:
; SRAM 192Kbytes
RW_IRAM_ALL SRAM_START (SRAM1_SIZE + SRAM2_SIZE + SRAM3_SIZE)
{
.ANY (+RW +ZI)
*(bitbandable_ram)
*(dma_ram)
}
Removing the .ANY selector from the CCM region requiring object to be explicitly located there using the core_coupled_ram named section.