umbhai,
ALARA=As low as reasonably achievable.
Time-Distance-Shielding.
To minimize radiation exposure you practice ALARA by limiting the time spent near the source of radiation, increasing the distance from the source and yes, using shielding when necessary and practical.
If other options exist, asking people to pick up higher doses of radiation is unacceptable. Can the RT crew(s) set up simutaneously and exit the area, then make the shots at the same time? Then both crews enter together to move to the next set up.
If you rely on just lead shielding to be the total ALARA practice and there is ONE mishap, the exposed individual's health could be adversely affected forever. I know (knew) a man that was unintentionally exposed to a source while performing RT. He was in the boiler and the RT crew didn't clear the boiler before making the shot and he turned around and was facing the 'pill'. (through a hand hole)
Lead is an excellent barrier to radiation but if the individual isn't fully behind the barrier, the results could be fatal.
We don't know the atmosphere (layout) of the area but if you were able to set lead shielding in place and record the radiation, if any, on the opposite side of the lead while making a shot, then you would know how much, if any, radiation the individuals would recieve. Basically, perform a mock-up.
Is UT, instead of RT, not an option?
Sorry for the delayed response, but my reply might help someone in the future in a similar situation. I have worked many RT jobs like this with multiple sources. Our solution was to set-up the cameras in the same general area, and coordinate the exposures being careful of the direction of the primary beams. Meaning both crews would position film, return to a common safe area and crank out both cameras. When both exposures were complete the process was repeated. The only additional shielding used was to either a) to reduce back-scatter from adjacent tubes or a wall, or b) shield one cassette from the secondary source.
By the way, what was your solution and how did it work out?